EGU Blogs - Recent Division Posts

Doing flood frequency hydrology in a non-stationary climate

Christina Orieschnig — Fri, 03 Apr 2026 09:47:42 +0000

A robust estimation of probabilities of extreme floods is the Holy Grail in flood hydrology in view of limited available observations, variability of climate, and complexity of flood generation processes in catchments. Flood frequency hydrology, spearheaded in the past decades by Ralf Merz and Günter Blöschl, offers a powerful toolbox to enhance the reliability of flood probability estimates by considering past historical floods (temporal information expansion), learning from similar neighbouring catchments that have longer observational records (spatial information expansion), and accounting for the different frequency of various flood types (causal information expansion). However, climate change comes as an additional hurdle - it undermines the fundamental stationarity assumption in our traditional extreme value statistics and challenges flood frequency hydrology. We face a situation in which already limited past observations become even less suitable for guiding us into the future. Additionally, changes in dominant flood types may affect spatial and causal information expansion. Estimates of flood probabilities in future climate are urgently needed for adjustment of flood protection infrastructure (e.g., dikes, dam spillways), flood hazard and risk maps, and flood risk management plans. So, how can we move forward?

Ingredients for “cooking” future flood probabilities

Climate models offer plenty of scenario simulations, yet they all have their limitations in terms of spatial resolution and length of time series, covering a specific time period which can be assumed stationary. This is, however, needed for classical extreme value statistics. For example, a 30-year period in the future climate is typically covered by a single scenario / model realization which is equivalent to a 30-year observational record - certainly not enough for a robust estimation of the probability of extreme floods. Statistical hydrology excelled in the development of weather generators - stochastic models trained on observed or simulated data to produce very long synthetic weather series. They can bridge spatial scales and generate weather fields within the assumed range of climate variability, retaining the key statistics of training datasets. Finally, hydrological models are continuously advancing by incorporating sophisticated process descriptions, discretizations, and parameter optimizations. These three ripe fruits are our key ingredients for “cooking” the probabilities of future floods. The “mixing pot” for this shake was actually designed long ago by Peter S. Eagleson in 1972 in his seminal paper laying the foundation of the Derived Flood Frequency Analysis (DFFA), where flood probability distributions were modelled based on the distribution of climatic and catchment variables. Basically, a hydrological model driven by climate variables delivers the simulated flood series for statistical analysis. So, what is the recipe?

Bringing ingredients into a mixing pot

In DFFA, we drive a hydrological model for a catchment of interest with sufficiently long weather series to obtain an empirical distribution of flood flows, as was for instance shown by Sarka Blazkova and Keith Beven for present climate conditions. The central idea for the cooking recipe of future flood probabilities is to inform a stochastic weather generator about the future climate state as simulated by deterministic climate models. In the work by Viet Dung Nguyen and colleagues, we developed such a climate-informed weather generator by conditioning the precipitation of every single day on large-scale circulation patterns and on regional average daily temperature. This reflects the dynamic and thermodynamic states of the atmosphere and largely contains the climate change signal. Long, synthetically generated weather fields representing a future climate state drive a time-continuous hydrological model to derive empirical flood distributions.

The beauty of the recipe

The beauty of this recipe has several facettes.

First, the weather generator is informed by climate model variables such as atmospheric pressure and surface temperature simulated with high reliability. Both also carry a large share of information on climate change signals relevant for flood generation.

Second, the weather generator not only produces very long weather series, which are hardly ever available from physically-based climate model simulations. It can also directly bridge the scale between global climate models and local weather, acting as a downscaler. This shortcut makes it computationally very attractive in comparison to regional climate simulations.

Finally, time-continuous hydrologic simulations in the order of several thousand years of daily time-steps, driven by the weather generator, implicitly integrate temporal, spatial, and causal information expansion into the derived flood frequency. The temporal expansion is straightforward and results from long-term simulation. The spatial expansion emerges from the spatial dependence structure of weather variables, i.e., the weather generator learns to produce heavy rainfall at locations close to observed heavy storms. Flood types emerge in the hydrological simulations with their respective frequencies through the combination of atmospheric drivers and catchment state evolution.

I believe that with this recipe, we have found an elegant way to estimate future flood probabilities by leveraging the advances of climate science, statistical hydrology, and hydrological modelling, following the guiding light of flood frequency hydrology. Yet, the robustness of the approach needs further thorough evaluation.

When a major climate event goes almost unnoticed: the elusive 8.2 ka signal in southern France stalagmites

Shalenys Bedoya — Thu, 02 Apr 2026 09:27:53 +0000

Around 8,200 years ago, the climate of the Northern Hemisphere experienced an abrupt disturbance. In Greenland ice cores, the signal is unmistakable: a rapid drop in temperatures, followed by a gradual return to previous conditions. This episode, which lasted about 150 years, is known as the 8.2 ka event (“ka” meaning thousand years before 1950). It is often described as the most prominent climate perturbation of the Holocene (the last ~11,700 years). The widely accepted explanation involves a massive release of freshwater from proglacial lakes (lakes formed at the margins of retreating ice sheets) in North America into the North Atlantic. This sudden freshwater input altered the isotopic composition (the ratio of different forms of oxygen atoms) of surface ocean waters and slowed the ocean circulation that transports heat northward, the Atlantic Meridional Overturning Circulation (AMOC). The result was rapid cooling over Greenland and surrounding regions. These changes were likely transmitted to Europe through atmospheric circulation, particularly via the westerly winds (i.e., strong prevailing winds blowing from west to east in the mid-latitudes). Yet one long-standing puzzle remains: the 8.2 ka event does not appear clearly everywhere. Along the European Atlantic margin (Iberian Peninsula, United Kingdom, western France), it is clearly recorded in multiple natural archives. Closer to the western Mediterranean, however, the signal often becomes weak, ambiguous… or absent. Does this difference reflect a genuinely weaker climatic impact, or simply differences in how natural archives record climate signals? In our study, published in Climate of the Past, we investigated this question using two high-resolution, multiproxy (multiple climate indicators) stalagmite records from southern France (Ardèche). We went in search for the 8.2 ka signal — but nothing stood out in our time series at this time. We therefore explored several possible explanations for this absence.

Reading climate in cave deposits

Our study is based on two stalagmites (mineral deposits that grow upward from cave floors) from neighboring caves in the Ardèche region of southeastern France: Saint-Marcel Cave and Aven d'Orgnac (Figure 1). [caption id="attachment_5458" align="alignleft" width="400"] Figure1. View of the Ardèche Gorges. The studied stalagmites come from caves formed within the limestone plateau, incised by the Ardèche River. Photo by Wouter Tolenaars via PxHere (CC0 1.0 Universal Public Domain Dedication).[/caption] These caves are located on a limestone plateau roughly 100 km from the Mediterranean Sea. The region receives precipitation from both Atlantic air masses, transported by the westerlies, and Mediterranean systems, particularly during intense autumn rainfall events known locally as “Cévenol episodes.” As rain water infiltrates the soil and hostrock above a cave, limestone is dissolved. When the infiltration water encounters a cavern in the hostrock, it drips from the ceiling onto the cave floor, where calcite layers are deposited to form stalagmites. The calcite preserves information about surface environmental conditions, including soil biological activity, hydrological balance, temperature, and the origin of precipitation. By measuring a stalagmite’s geochemistry millimetre by millimetre along its growth axis, and determining its age using uranium-thorium methods, it is possible to reconstruct environmental and climatic variations at decadal to multi-decadal resolution. We applied this approach to the period between 11,500 and 5,500 years ago. When we analyzed oxygen and carbon isotopes, as well as elemental ratios such as magnesium-to-calcium and strontium-to-calcium ratios, in both stalagmites, no clear disruption appeared around 8,200 years ago. Small variations are present, but they remain within the range of background fluctuations of the preceding millennium.

Why is the signal missing?

Several explanations are possible, and they are not mutually exclusive. 1. A genuinely limited climate impact in southern France The 8.2 ka signal appears more strongly expressed in sites located near the North Atlantic Ocean and in mountainous regions. Local conditions at those sites likely enhance the clarity of the oxygen isotope signal transmitted by precipitation and/or amplify the climatic effects of the event. Ardèche does not share these characteristics. Climate model simulations suggest that cooling in the Mediterranean region during the 8.2 ka event may have been modest (on the order of half a degree Celsius). Such a small change may have been insufficient to generate a significant response in our geochemical proxies. Additionally, if the 8.2 ka event involved a southward shift of the westerly storm tracks, one might expect detectable hydrological changes. It is possible, however, that Ardèche remained under the influence of the westerlies despite a shift in their average trajectory. As a transitional zone, it may not have experienced significant hydrological change. 2. A Mediterranean “buffer” effect A substantial proportion of precipitation in Ardèche originates from the Mediterranean. Because the 8.2 ka event was linked to changes in the North Atlantic, the Mediterranean component of cave recharge may have dampened or masked any oxygen isotope signal associated with altered Atlantic-sourced rainfall. However, this explanation alone does not fully account for the absence of a clear climatic — particularly hydrological — signal in the other proxies we measured, such as carbon isotopes and trace elements. 3. An archive recording bias A third explanation relates to the nature of climate archives themselves. Parameters such as temperature, and precipitation amount, source and seasonality, are not recorded directly or unambiguously. Instead, stalagmite proxies respond to a cascade of processes: infiltration through soils, residence time and mixing within the karst system (the network of fractures and cavities in limestone), water–rock interactions, and finally calcite precipitation inside the cave. At each step, the original climate signal can be amplified or attenuated. A climate change may therefore go undetected if the proxies analyzed are not sensitive to the variable(s) that actually changed (for example, seasonality rather than annual precipitation totals). In short, the absence of a clear signal does not necessarily mean the absence of climate change. It may also reflect how climate information is filtered and archived within the karst system.

Conclusion

By combining multiple proxies in two stalagmites from neighboring caves, our aim was to reduce the risk of biased interpretation by site-specific effects or by the limitations of a single proxy. In spite of this replicated high-resolution, well-dated multiproxy approach, the 8.2 ka event could not be identified in our speleothem records and thus its climatic impacts remain elusive in southern France. This does not mean that the event had no impact in the region, or more broadly in the Mediterranean. Rather, it suggests that its expression was likely weaker, more seasonal, or more complex than is observed elsewhere. Climate history is not uniform. It is shaped by regional contrasts and local filters, and is reconstructed from archives with different sensitivities. Understanding these nuances is essential not only for reconstructing past climate change, but also for anticipating how future perturbations may manifest differently across regions. The 8.2 ka event — triggered by a massive freshwater input into the North Atlantic — resonates strongly with present-day concerns about the melting of the Greenland ice sheet and a potential weakening of the Atlantic Meridional Overturning Circulation. In this sense, it provides a valuable natural analogue for exploring how a future perturbation of ocean circulation might — or might not — translate into regional climate impacts across Europe.

This post has been edited by the editorial board.

References 

Passelergue, M., Couchoud, I., Drysdale, R. N., Hellstrom, J., Hoffmann, D. L., and Greig, A.: The elusive 8.2 ka event in speleothems from southern France, Clim. Past, 22, 315–338, https://doi.org/10.5194/cp-22-315-2026, 2026.

Exploring Earth's interior with analogue models: The case of slow earthquakes

yutosasaki — Thu, 02 Apr 2026 09:00:49 +0000

Have you ever heard of "analogue modelling"? In solid Earth science, directly observing the Earth's interior is challenging, and the analogue modelling approach often overcomes this limitation by using alternative systems analogous to natural phenomena. By identifying fundamental mechanisms in these tractable systems, we can apply physical scaling laws to understand processes deep within the Earth. This broad concept encompasses not only laboratory experiments but also numerical models and even geological studies. In this post, we explore how analogue modelling helps us understand a fundamental puzzle: the mysterious statistics of regular and slow earthquakes.

What is analogue modelling?

Directly observing the interior of Earth and planets is quite difficult due to the opacity, high temperature, and high pressure. While many experimental attempts to recreate the Earth's interior conditions have yielded numerous important insights, they are also difficult due to technical limitations. Analog modelling offers a practical alternative to overcome these difficulties and to elucidate underlying physics. In solid Earth science, analogue modelling studies natural phenomena (such as earthquake dynamics) using systems in which some complex elements of reality have been modified or removed, while the essential principles and elementary processes are considered to be shared with nature. The approach aims to identify underlying physical mechanisms and governing laws, then apply these common principles and processes to the Earth's interior through physical scaling. In other words, it investigates the underlying physics using systems where analogy or similarity laws hold for certain aspects of the target phenomenon. In this sense, high-pressure/high-temperature experiments are also a kind of analogue in terms of system size, strain rate, impurity, etc. Moreover, analogue modelling is not limited to laboratory experiments: highly simplified physical systems like cellular automata can serve as numerical analogues, and geological studies examining high-pressure/high-temperature rock bodies exhumed from the Earth's interior could also be considered a type of deep Earth analogue. Depending on the degree of simplification, the model may appear unrelated to geophysical phenomena at first glance; however, it can share universal physical principles in certain aspects, which can serve as a basis for understanding the underlying mechanisms (Fig. 1). Although there are numerous analogue model systems and we cannot review all of them here, you may, for example, refer to Reber et al. (2020), as well as the Wikipedia article on "Rock analogs for structural geology". In this blog post, we introduce some analogue systems that have been used to explore the statistical properties of earthquakes, which should reflect the underlying mechanism and influence the probabilistic evaluation of seismicity. [caption id="attachment_13049" align="alignnone" width="1600"] Figure 1. Various analogue systems, ranging from real nature to simplified numerical models. The level of analogy changes continuously with the degree of simplification. This figure is created by Yuto Sasak and includes elements adapted from Zhao (2019), Weng et al. (2024), Von-Hagke et al. (2019), Sasaki et al. (2025), Papadopoulos et al. (2018), and Kazarnikov et al. (2025).[/caption]

Mysterious differences between two kinds of earthquakes

Earthquakes are currently proposed to be classified into two types—regular earthquakes and slow earthquakes—based on the scaling relationship between their seismic moment M₀ (event size) and duration T, as shown in Fig. 2 Left (Ide & Beroza, 2023). Slow earthquakes have longer durations than regular earthquakes of equivalent size, and this is why slow earthquakes are referred to as "slow". In addition, some slow earthquakes seem to follow a size-frequency distribution qualitatively different from that of regular earthquakes, a power-law size distribution known as the Gutenberg–Richter (GR) relation, as shown in Fig. 2 Right (Chestler & Creager, 2017). Note that, in some cases, they may follow the power-law distribution with a similar power exponent to regular ones (Chiba, 2020). No one knows what causes these differences between regular and slow earthquakes. Nevertheless, analogue modeling has contributed to elucidating the processes underlying these statistics. [caption id="attachment_13065" align="aligncenter" width="1600"] Figure 2. Statistical differences between regular (black data) and slow (red data) earthquakes. (Left) Relationship between seismic moment and duration. (Right) Cumulative frequency distribution of seismic moment in Cascadia on a semi-log scale. LFE stands for low-frequency earthquakes, a type of slow earthquake. Note that the x-axis range differs depending on the data type. The inset shows the same data on a log-log scale, with identical axis ranges for all data types. Data are taken from Ide & Beroza (2023) and its references, Kanamori & Anderson (1975), Chestler & Creager (2017), Hyndman et al. (2003).[/caption]

Analogue system exploring size-frequency distributions of earthquakes

The mysterious power-law size distribution of regular earthquakes has long been investigated. In 1967, an analogue model provided a clue to understanding the problem. This model is called a spring-block model or Burridge-Knopoff model (Burridge & Knopoff, 1967). The model consists of multiple blocks placed on a lower surface, which are connected to each other and to an upper driving plate via springs, as shown in Fig. 3 (Mascia & Moschetta, 2020). You can see how this model behaves and how it is analogous to seismogenic slip bursts on YouTube, for both single-block and multiple-block cases. This model, along with cellular automaton models inspired by it (Olami et al., 1992), has increasingly succeeded in explaining the observed power-law distributions. Moreover, shear experiments using beads analogous to fault gouges (Geller et al., 2015; Korkolis et al., 2021) also reproduce and explain the observed power-law distribution for regular earthquakes. In this way, analogue modeling has contributed to understanding the statistical properties of regular earthquakes. The question then arises: what about slow earthquakes? [caption id="attachment_13053" align="alignnone" width="1600"] Figure 3. Schematic of the Burridge–Knopoff model. From Mascia & Moschetta (2020).[/caption]

How could analogue modelling elucidate the mysterious origin of slow earthquakes?

Compared to regular earthquakes, deeper source regions of slow earthquakes are thought to contain abundant viscous phases, e.g., ductile minerals and fluids. Some metamorphic rocks that have experienced the corresponding conditions of pressure, temperature, and tectonic setting exhibit block-in-matrix fabric (Fig. 4), where rigid blocks and soft matrix exhibit brittle failure and viscous flow structures, respectively. To construct an analogue system corresponding to such a geological structure, Reber et al. (2014) and Birren & Reber (2019) performed analogue experiments using acrylic discs embedded in a viscous fluid and a mixture of microgel particles with interstitial fluid, respectively. They captured the transition between seismogenic-like stick-slip and creep behaviors. Inspired by their works, the mixture of hydrogel spheres and viscous fluid (the feature image above) has been found to exhibit statistical properties similar to those of slow earthquakes, as shown in Fig.5 (Sasaki et al., 2025). Although the underlying physics remains controversial even today, combining analogue modeling based on geological insights with high-temperature, high-pressure rock experiments could help explain the geophysical observations and potentially elucidate the enigmatic mechanisms of both regular and slow earthquakes. This would strengthen the probabilistic evaluation of the interaction between their seismicity and help with disaster preparedness, as well as the physical mechanism of multiphase flow and the origin of shear zones in plate tectonics. [caption id="attachment_13083" align="alignnone" width="1526"] Figure 4. Block-in-matrix fabric within a shear zone that has experienced conditions characteristic of slow earthquake source regions (blueschist facies). Credits: Yuto Sasaki, 2026.[/caption] [caption id="attachment_13090" align="alignnone" width="1600"] Figure 5. Hydrogel-fluid mixture qualitatively exhibiting the slow-earthquake statistics: (Left) Moment-frequency distribution, (Right) moment-duration relationship (Sasaki & Katsuragi, 2025).[/caption]

References

Birren, T., & Reber, J. E. (2019). The impact of rheology on the transition from stick‐slip to creep in a semibrittle analog. Journal of Geophysical Research: Solid Earth, 124(3), 3144-3154. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JB016914 Burridge, R., & Knopoff, L. (1967). Model and theoretical seismicity. Bulletin of the seismological society of america, 57(3), 341-371. https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/57/3/341/116471/Model-and-theoretical-seismicity Chestler, S. R., & Creager, K. C. (2017). Evidence for a scale‐limited low‐frequency earthquake source process. Journal of Geophysical Research: Solid Earth, 122(4), 3099-3114. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JB013717 Chiba, K. (2020). Stress state along the western Nankai Trough subduction zone inferred from b-values, long-term slow-slip events, and low-frequency earthquakes. Earth, Planets and Space, 72(1), 3. https://link.springer.com/article/10.1186/s40623-020-1130-7 Geller, D. A., Ecke, R. E., Dahmen, K. A., & Backhaus, S. (2015). Stick-slip behavior in a continuum-granular experiment. Physical Review E, 92(6), 060201. https://journals.aps.org/pre/abstract/10.1103/PhysRevE.92.060201 Gutenberg, B. & Richter, C. F. (1944). Frequency of earthquakes in California. Bulletin of the Seismological Society of America, 34, 185–188. https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/34/4/185/101140/Frequency-of-earthquakes-in-California Hyndman, R. D., S.Mazzotti, D.Weichert, and G. C.Rogers (2003). Frequency of large crustal earthquakes in Puget Sound–Southern Georgia Strait predicted from geodetic and geological deformation rates. Journal of Geophysical Research: Solid Earth, 108, 2033. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2001JB001710 Ide, S., & Beroza, G. C. (2023). Slow earthquake scaling reconsidered as a boundary between distinct modes of rupture propagation. Proceedings of the National Academy of Sciences, 120(32), e2222102120. https://www.pnas.org/doi/10.1073/pnas.2222102120 Kanamori, H., & Anderson, D. L. (1975). Theoretical basis of some empirical relations in seismology. Bulletin of the Seismological Society of America (1975) 65 (5): 1073–1095. https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/65/5/1073/117458/Theoretical-basis-of-some-empirical-relations-in Kazarnikov, A., Ray, N., Haario, H., Lappalainen, J., & Rupp, A. (2025). Parameter estimation for cellular automata. Japanese Journal of Statistics and Data Science, 1-26. https://link.springer.com/article/10.1007/s42081-024-00283-w Korkolis, E., Niemeijer, A. R., Paulssen, H., & Trampert, J. (2021). A laboratory perspective on the Gutenberg‐Richter and characteristic earthquake models. Journal of Geophysical Research: Solid Earth, 126(8), e2021JB021730. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JB021730 Mascia, C., & Moschetta, P. (2020). Numerical evidences of almost convergence of wave speeds for the Burridge–Knopoff model. SN Applied Sciences, 2(12), 2053. https://link.springer.com/article/10.1007/s42452-020-03856-y Olami, Z., Feder, H. J. S., & Christensen, K. (1992). Self-organized criticality in a continuous, nonconservative cellular automaton modeling earthquakes. Physical Review Letters, 68(8), 1244. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.68.1244 Papadopoulos, L., Porter, M. A., Daniels, K. E., & Bassett, D. S. (2018). Network analysis of particles and grains. Journal of Complex Networks, 6(4), 485-565. https://academic.oup.com/comnet/article/6/4/485/4959635 Reber, J. E., Cooke, M. L., & Dooley, T. P. (2020). What model material to use? A Review on rock analogs for structural geology and tectonics. Earth-Science Reviews, 202, 103107. https://www.sciencedirect.com/science/article/abs/pii/S0012825219306026 Reber, J. E., Hayman, N. W., & Lavier, L. L. (2014). Stick‐slip and creep behavior in lubricated granular material: Insights into the brittle‐ductile transition. Geophysical Research Letters, 41(10), 3471-3477. https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2014GL059832 Sasaki, Y., & Katsuragi, H. (2025). Origin of slow earthquake statistics in low-friction soft granular shear. Nature Communications, 16(1), 10236. https://www.nature.com/articles/s41467-025-65230-z Sasaki, Y., Takei, Y., McCarthy, C., & Rudge, J. F. (2019). Experimental study of dislocation damping using a rock analogue. Journal of Geophysical Research: Solid Earth, 124(7), 6523-6541. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018JB016906 Von Hagke, C., Kettermann, M., Bitsch, N., Bücken, D., Weismüller, C., & Urai, J. L. (2019). The effect of obliquity of slip in normal faults on distribution of open fractures. Frontiers in Earth Science, 7, 18. https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2019.00018/full Weng, M. C., Lin, S. S., Lee, C. S., Wu, W. H., Li, J. H., & Liu, C. H. (2024). An anisotropic thermal–mechanical coupling failure criterion for slate. Rock Mechanics and Rock Engineering, 57(10), 8157-8177. https://link.springer.com/article/10.1007/s00603-024-03992-6 Zhao, D. (2019). Importance of later phases in seismic tomography. Physics of the Earth and Planetary Interiors, 296, 106314. https://www.sciencedirect.com/science/article/pii/S0031920119302195 Attila Gergely (2022). "1D Burridge-Knopoff experiment 91" (accessed 1 April, 2026). https://www.youtube.com/watch?v=3auyKm_uZ1E Institut für Geowissenschaften & RUHR-UNIVERSITÄT BOCHUM (2025). "Stick-slip: earthquakes in the laboratory using a spring-block slider" (accessed 1 April, 2026). https://www.youtube.com/watch?v=AylMEWgVAGA Wikipedia contributors (2026). "Rock analogs for structural geology" Wikipedia (accessed 1 April, 2026). https://en.wikipedia.org/wiki/Rock_analogs_for_structural_geology

Unveiling Volcanic Slopes: Exploring Landslide Hazards in Santorini Island, Greece

Emma Lodes — Wed, 01 Apr 2026 09:00:27 +0000

by Stratis (Efstratios) Karantanellis, Professor, Geohazards and Remote Sensing Lab, Department of Geological Sciences at California State University, Fullerton. Email: ekarantanellis@fullerton.edu, website: https://sites.google.com/view/stratiskarantanellis Santorini is one of those places that doesn’t quite feel real at first glance. White houses stacked on cliffs, blue domes, the Aegean stretching out in every direction. But once you step closer to the edge, especially along the caldera, you start to notice something else: the landscape is constantly moving. Earlier this year, my team and I headed to Santorini to look at landslide hazards. I spent a lot of time around Red Beach, where steep red volcanic cliffs drop straight into the sea. It’s a stunning place, but also one where rockfalls are frequent enough to close access from time to time. What we wanted to understand wasn’t just where failures might occur, but also how these slopes evolve and whether we can track that change in a meaningful, measurable way. Most mornings started early, before the wind picked up and before the first wave of tourists arrived. Red Beach at sunrise feels like a different place, quiet, almost still, even though you know the slopes above you are anything but stable. Geology explains much of that instability. The cliffs are made up of layered volcanic deposits, ash, pumice, lava flows, sitting on weaker materials. They’re fractured, weathered, and in many places, already close to failure. But identifying exactly where and how things might move isn’t straightforward, especially when much of the terrain is too steep to access safely. This is where our approach is built on earlier work we’ve done using UAVs for object-based landslide analysis. Instead of just mapping the landscape visually, we treat it as a collection of “objects”, distinct geomorphic units that can be classified based on their geometry, roughness, slope, and texture. Using drone imagery and LiDAR, we can segment the terrain into meaningful pieces: intact rock masses, loose debris, scarps, and accumulation zones. In Santorini, that conceptual approach became even more powerful when combined with high-resolution 3D data. Flying along the caldera cliffs wasn’t always easy, the winds had their own plans, but once we captured the data, we could reconstruct the slopes in remarkable detail. Features that would be easy to miss in the field, minor fractures, small detachments, and surface changes, stood out clearly in the point clouds. But the real shift came when we stopped thinking of these objects as static. We repeated our surveys and started comparing them. Instead of a single 3D model, we now have multiple snapshots of the same slope taken at different times. That’s where things moved from 3D into something closer to 4D. [caption id="attachment_2825" align="alignright" width="1280"] Figure 2. 3D surface change model of the Red Beach, Santorini, Greece. PC: Stratis
Karantanellis[/caption] I remember one specific spot at Red Beach. After a light rain, we revisited an area we had already scanned. Standing there, nothing looked different. But when we processed the data and ran a comparison, small changes appeared, tiny volumes of material had shifted, and the boundaries of certain “objects” had subtly changed. That’s where the connection to object-based analysis really clicked. It’s one thing to map a landslide scarp or a deposit patch; it’s another to track how those features evolve. Objects can grow, shrink, merge, or disappear entirely. By combining object-based segmentation with multitemporal 3D data, we’re no longer just identifying hazards; we’re observing how they develop. Of course, the fieldwork itself had its usual mix of challenges and lighter moments. One drone decided to land in a patch of bushes (a good outcome, all things considered). Tourists occasionally gathered, assuming we were filming something cinematic rather than scanning unstable slopes. And residents shared stories of past rockfalls, blocked roads, and closed paths, which grounded our data in real experience. Back in the lab, we processed everything into terrain models and ran change detection analyses. The patterns were subtle but consistent. Certain areas kept showing low-level activity. Not major failures, but enough movement to suggest that these slopes are continuously adjusting. That’s really the key takeaway. Landslides aren’t always sudden, catastrophic events. Often, they’re the result of small, incremental changes building up over time, and those are exactly the kinds of changes that traditional methods tend to miss. This is where continuous monitoring becomes essential. With extreme weather events becoming more frequent and intense, the conditions that trigger slope instability, heavy rainfall, rapid saturation, and even seismic responses are also becoming less predictable. Having the ability to repeatedly capture high-resolution 3D data means we’re no longer limited to before-and-after comparisons. Instead, we can begin to track how instability develops, step by step, and identify early signals that might precede larger failures. What makes this particularly powerful is the combination of that temporal dimension with object-based analysis. It’s not just about detecting that something moved; it’s about understanding what moved, how, and where within the slope system. That level of detail opens the door to more targeted hazard assessments and, potentially, more effective mitigation strategies. What stayed with me from Santorini wasn’t just the landscape, but the shift in how we study it. By combining UAV-based object analysis with repeated 3D surveys, geomorphology becomes dynamic and measurable rather than purely descriptive. Standing above Red Beach, it’s clear the cliffs won’t stay the same. What’s new is that we can now follow those changes as they happen, one dataset at a time, and that opens the door to understanding, and maybe even anticipating, the next failure. Please contact Emma Lodes and Anna van den Broek (GM blog editor, elodes@asu.edu, a.j.vandenbroek@uu.nl), if you’d like to contribute on this blog!

The sassy scientist: we regret to inform you

The Sassy Scientist — Wed, 01 Apr 2026 08:00:22 +0000

With the winds of change brought by a new season, I'm back to help my readers to get out from dispair. This time a reader ask:

Dear Sassy scientist,

How do I deal with rejection during a job hunt?

Dear Sarah, I hear you writing from the edge of despair. Let’s be honest: you’ve chosen the scenic route to career purgatory. Nevermind watching your lifelong friends enjoying their permanent contracts, job stability and newly bought houses (kudos to them, I guess). You decided to inflict yourself with the pain of job uncertainty. Reduced opportunities in a saturated job market with few academic positions, senior researchers taking multiple positions, professors clinging to their positions past their retirement age like first-edition Pokémon cards and scarce government funding in the name of "efficiency”. Yes, it’s all a giant compost heap. I have given this a thought. It’s grim, let’s face it. From my own experience (and countless catharsis sessions with my fellow friends over some pints), I’ve concluded that postdoc hunting feels like filling one of those sticker albums we had as kids (I won’t reveal my most treasured one; no need to betray my age): each sticker being a reason or circumstance related to the experience of looking for the next postdoc. I’m sure you or our fellow readers hit one of these at some point:

The one with the poorly tailored application: you were in a rush, you cut corners and decided to describe yourself as a “team player” in your cover letter. This will steal some sighs from the PI reading your application. My advice to you if you’ve been here: do your homework and customize your application to the post you’re applying. It matters.
The one with the fit mismatch: with jobpools with the size of detrital zircons and our hyper-specialised profiles it’s highly likely you will apply to positions that only vaguely resemble your expertise. Sometimes it’s just not your match, and that’s that.
The one with the ghosting: You spent days customizing your application, hit submit… and then nothing. Radio silence for months. Surely someone was hired during that geological timescale, but sending a follow-up message wouldn’t hurt anyone. To be fair, sometimes PIs legally cannot follow up unless the chosen one has formally accepted. If the suspense is killing you, a follow up message might do the job.
The one with the internal candidate: Some positions must be advertised even though they’re already earmarked for a continuing postdoc or a soon-to-graduate PhD. Can you avoid wasting your time? Maybe. A quick cold email to the PI before applying can reveal whether the job is real or, well… merely filling space on a website.
The one with the vanishing funding. You put the effort into writing and submitting the proposal. However, in times of political uncertainties and governments changing their minds on science policies as three-year-olds, it might be that the grant gets delayed or even cancelled. All to do is regroup (and refrain from voting for that party in the next elections).

This list isn’t exhaustive, but you got the idea. You came looking for advice, right? And here I am, just rambling about the status quo… I leave you with my two pennies, free of toxic positivity. While rejection hurts, it’s not a sign of your potential or even your identity: keep perspective (“Don't despair you'll get it right tomorrow night”). Reflect on what you can control and what’s out of control (about the latter: probably more than you think). Stay connected with the people around you (we need to embrace how to fail) and keep reaching out to potential PIs. And most importantly don’t let the system bring you down. We need more people like you, not fewer. Yours truly, Sassy Scientist

CLOUDLAB: Cloud research in a natural laboratory

nadjaomanovic — Tue, 31 Mar 2026 07:25:25 +0000

It’s murky grey, windy, and freezing when we head out into the countryside of the Swiss pre-Alps. We are looking for low hanging clouds to serve as our natural laboratory. Wintertime low stratus clouds can cover Switzerland for days. This type of cloud is stable with temperatures below 0 ºC and it contains plenty of liquid cloud droplets, but no ice crystals. These are the perfect background conditions for starting our experiments (see Figure 1, left). We launch an uncrewed aerial vehicle (UAV) to seed the cloud with aerosol particles. These aerosol particles trigger the formation of ice crystals. As there was no ice present in the natural cloud, we can attribute all the observed ice crystals to the artificial perturbation. This allows us to study ice crystal growth in a controlled and reproducible manner under real world conditions. So, instead of bringing the cloud into the lab, CLOUDLAB takes the lab into the cloud. But why are we interested in ice growth processes? They are essential for the formation of precipitation (Mülmenstädt et al., 2015). Accurate precipitation forecasts are vital in order to reduce their risks and damages. Improving our understanding of ice growth processes on the microphysical scale will help us to represent them more accurately in numerical weather models.

The key role of ice in precipitation formation

Starting with a cloud consisting of many tiny, purely liquid cloud droplets, it is rare, that the cloud droplets grow large enough to fall out as rain. When this cloud cools down to below 0 ºC, counter-intuitively, its cloud droplets do not freeze immediately. A temperature of around -38 ºC is needed, to overcome the energy barrier of rearranging the water molecules into the hexagonal ice lattice. Thus, cloud droplets remain in a meta-stable liquid state between 0 ºC and -38 ºC and are referred to as supercooled cloud droplets. In the atmosphere many solid aerosol particles are suspended, which are needed to help to overcome the energy barrier. If a supercooled cloud droplet merges with a mineral dust particle, for example, the solid surface reduces the energy barrier and the cloud droplet freezes at negative temperatures much higher than -38ºC. Therefore, liquid water and ice can coexist in clouds with temperatures between 0 ºC and -38 ºC. These so-called mixed-phase clouds are particularly favorable for fast growing ice crystals, which subsequently initiate precipitation. This efficiency boils down to differences in required supersaturations, i.e., water vapor reservoirs, for the growth cloud droplet and ice crystals. Here, we find a peculiar process: the Wegener-Bergeron-Findeisen (WBF) process, which takes place in conditions, where cloud droplets experience a subsaturated environment, while ice crystals still are in supersaturated conditions. Hence, ice crystals will grow through vapor deposition onto their surface, while cloud droplets evaporate replenishing the water vapor reservoir (see Figure 1, right). This way, ice crystals can reach fast precipitable sizes; either as snow or they melt and become rain. In contrast, processes that do not involve the ice phase are less effective in producing precipitation. As a result, more than 70 % of precipitation in the mid-latitudes originates from the ice phase (Mülmenstädt et al., 2015). [caption id="attachment_1998" align="aligncenter" width="1024"] Figure 1: Top view of a low stratus cloud covering Switzerland (left). Picture taken by CLOUDLAB. Image depicting the WBF process with an ice crystal in the center surrounded by cloud droplets. Image taken from www.snowcrystals.com/.[/caption]

Our mission

We want to quantify ice growth processes in natural clouds in a controlled manner. Therefore we target in Switzerland frequently occurring stratiform liquid-only clouds, so-called low stratus clouds, which form in the lowest 2 km of the atmosphere. They are characterized by a constant wind direction and can persist for several days. If cloud top temperatures are below -5 ºC, we head out into the field and start our experiments. To start an experiment we emit aerosol particles by a UAV into the cloud layer. The wind direction and wind speed define where and how far upwind of the main field site we seed the cloud. At the main field site there is a suite of in situ and remote sensing instruments waiting to observe the advected seeding plume. This experimental set-up is visualized in Figure 2. On the ground, we have various remote sensing instruments, such as cloud radars, lidars, and radiometers. On a tethered balloon system flying inside the cloud there are in situ instruments such as a holographic camera to observe individual hydrometeors, an anemometer, and an aerosol particle spectrometer. These measurements are completed by radiosonde profiles and disdrometers on the ground to measure precipitation (Henneberger, Ramelli et al., 2023). So far, more than 90 cloud seeding experiments were conducted during the winters between 2021 and 2026. [caption id="attachment_1962" align="aligncenter" width="1024"] Figure 2: Overview of the cloud seeding experiments performed during CLOUDLAB: A seeding UAV releases seeding particles into the cloud, which initiates ice formation. The newly formed ice crystals can grow through the Wegener–Bergeron–Findeisen process. The seeded patch is characterized by a tethered balloon system (TBS), and remote sensing on the ground (Ramelli et al., 2024).[/caption]

Microphysical observations and model implications

Figure 3 shows different shapes of ice crystals observed during our experiments. Microphysical changes in the plume and meteorological conditions of the environment are measured simultaneously. This helps us to enhance our understanding of the WBF process under natural conditions. For example, we can analyse how the ice growth rates vary with temperature or liquid water content of the background cloud. Ramelli et al. (2024) found that the ice crystal growth rates in CLOUDLAB have a considerable larger variability than in previously published laboratory studies, which can potentially accelerate precipitation initiation. Moreover, the modeling world benefits from these observations. Omanovic et al. (2024) compared simulated cloud droplet and ice crystal number concentration to in situ measurements. They found that the simulated WBF process is slower in terms of changes in liquid water content and ice crystal sizes. Ultimately, these studies retrace the processes of ice formation and growth, but further investigation is still required to incorporate these findings in operational weather models. [caption id="attachment_1970" align="aligncenter" width="1024"] Figure 3: A randomly selected sample of ice crystal images observed by the holographic camera during seeding experiments (Ramelli et al., 2024).[/caption]

What's next?

As part of the next-generation CLOUDLAB team, we are currently out in the field. We are building on our colleagues' work by conducting observations over longer growth times and across a wider temperature range. Besides supercooled clouds, we also target clouds with warm cloud top temperatures to study processes only involving cloud droplets. Additionally, we measure how the radiative cloud properties evolve during an experiment, test different seeding materials, and analyse the chemical composition of water and ice collected in the cloud and on the ground. Lastly, we will chase the seeding plume with free floating balloons to observe its evolution along a Lagrangian trajectory. We therefore hope for many more cold, murky grey, and windy winters until 2029. Stay tuned for what findings we will reveal. :-)

Art, science, and seismic memory

EGU Seismology ECS Team — Mon, 30 Mar 2026 12:16:42 +0000

The contribution from Sergio León-Ríos, Associate Researcher at the Advanced Mining Technology Center (AMTC) at the University of Chile, where he does seismology research.

Introduction

Earthquakes and tsunamis are not only purely scientific geophysical phenomena. They are also deeply embedded in social memory, cultural narratives, and everyday life - especially in countries like Chile, where seismic activity is a constant presence. For the record, the strongest largest earthquake ever recorded by humanity (magnitude 9.5!) happened in Chile in 1960. While scientific research provides essential knowledge about how and why these events occur, art offers complementary ways of engaging with uncertainty, loss, resilience, and memory. When these two approaches come together, they can foster new forms of understanding and participation, helping to build more informed and resilient communities. The exhibition Seismic Inheritance emerges from this shared space between art and science. Rather than translating scientific results into simplified messages, the project creates a dialogue between artistic practice, historical archives, and contemporary geoscience. In doing so, it invites broader audiences to engage with seismic risk not only as an abstract concept, but as a lived and remembered experience—an essential step toward long-term disaster risk reduction. [caption id="attachment_12032" align="aligncenter" width="1024"] Main wall of the Seismic Inheritance exhibition.[/caption]

Seismic inheritance: an art and heritage exhibition on earthquakes and tsunamis in Chile

Seismic Inheritance is a project led by artists and researchers Ignacio Gutierrez Crocco and Sebastian Riffo Valdebenito, who, through DESARTES at the Research Center for Integrated Disaster Risk Management (CIGIDEN) and their own artistic practices, have developed a sustained body of work exploring the intersection between the arts and socio-natural disasters in Chile. The project is co-directed scientifically by seismologist Sergio Leon-Rios, researcher at the Advanced Mining Technology Center of the Universidad de Chile. [caption id="attachment_12039" align="aligncenter" width="1024"] Notebook from 1965 with annotations of the seismic station in Isla Decepcion island in Antarctica.[/caption] The exhibition represents a milestone, consolidating years of work rooted in artistic practice, research, and the construction of collective memory around disasters. Thanks to funding from the National Fund for Cultural and Artistic Development (2025 call) of Chile’s Ministry of Culture, this interdisciplinary initiative expands to include new partner institutions, such as the National Seismological Center (CSN), the Geophysical Department of the Universidad de Chile, the GeoTsunami Laboratory of the Pontificia Universidad Catolica de Valparaíso, and SHOA, the Hydrographic and Oceanographic Service of the Chilean Navy. Curated by Ignacio Gutierrez-Crocco, Sebastian Riffo-Valdebenito, and Sergio Leon-Rios, the exhibition brings together artworks created specifically for this show in dialogue with historically significant seismological and tsunami-related objects. Scientific instruments and archival materials are presented alongside contemporary artworks, creating a space where scientific knowledge and artistic interpretation intersect. [caption id="attachment_12037" align="aligncenter" width="768"] Soil peeling of the 1730 tsunami in Valparaiso, Chile occurred as a consequence of the earthquake magnitude 9.1-9.3 in Central Chile.[/caption] One of the most compelling aspects of Seismic Inheritance lies in these archival objects, drawn from the storage rooms of the collaborating institutions. Many of them have never been publicly displayed before and are now revisited through the lens of contemporary art, beyond their original scientific function. Field notebooks, filing folders, smoke and photographic cellulose seismograms from the 1960 earthquake, tide gauge records, hand-drawn diagrams exploring the relationship between lunar and solar positions and earthquakes, bulletins, correspondence, and tsunami sediments all form part of the exhibition. Exhibition design is led by Bastián Pérez, who is responsible for materializing this interdisciplinary curatorial vision and integrating the diverse elements into a cohesive spatial experience. [caption id="attachment_12040" align="aligncenter" width="683"] Bastian Perez, museum curator of Seismic Inheritance.[/caption] Seismic Inheritance was exhibited at the Museography Hall of the National Service for Disaster Prevention and Response (SENAPRED). This venue has previously hosted After the Fire (2025) and Post-Resilience (2024), both promoted by DESARTES, the Arts and Disasters unit within CIGIDEN. DESARTES aims to foster research, creation, and archiving of Chilean artworks linked to earthquakes, floods, tsunamis, and wildfires. Contemporary art, socio-natural disasters, scientific research, and seismological objects come together in this exhibition, which brings Chile’s seismic history and heritage into dialogue. Beyond contributing to memory and reflection, the exhibition invites audiences to engage with the subtle traces left by earthquakes and tsunamis, and with their deep presence in the country’s cultural narratives and imaginaries.

The artists

Seismic Inheritance presents six new works by artists from different generations and disciplines, each approaching seismic phenomena from distinct perspectives.

Constanza Alarcon Tennen presents The Tremor of the Pelicans, a sound piece inspired by a bird colony affected by the 2010 tsunami, questioning anthropocentric interpretations of catastrophe.
Rafael Guendelman Hales presents One Kilo of Beans Is Not a Failure, a video installation that confronts the official narrative of the 1985 earthquake, which occurred during Chile’s military dictatorship.
Fernanda Lopez Quilodran exhibits Involuntary Agitation, a choreographic and textile work that translates seismic and tide-gauge records from March 22, 1960, into bodily gestures and visual scores.
Diego Silva Rochefort, in Pangeo: Structural Failure, presents an installation activated by real-time data from the National Seismological Center, operating as a live seismograph and articulating a critique of urban negligence.
Paloma Villalobos Danessien, in The Waves, combines video and photography from the Maule and Cahuil regions, presenting post-tsunami memory through an unstable display that makes everyday life and precarity visible.
Natacha Cabellos Ricart creates A Prolonged Underground Noise Is Heard for Minutes, a reactive installation in which a 3D-printed hand, mounted on a rotating axis, scans the space in search of the latest earthquake—an exploration of territory, control, and technological sensitivity.

Beyond communication: building awareness and reducing risk

Projects like Seismic Inheritance show that the connection between art and science goes beyond outreach or dissemination. By opening scientific archives, instruments, and data to artistic reinterpretation, the exhibition creates spaces where knowledge is shared, questioned, and collectively experienced. Such a process helps transform abstract seismic concepts into tangible narratives, fostering curiosity, emotional engagement, and long-term awareness. In regions exposed to recurrent natural hazards, such engagement is crucial. Disaster risk reduction depends not only on scientific advances, but also on informed and engaged communities—communities that understand hazards, remember past events, and recognize their role in preparedness and resilience. By weaving together art, science, and memory, Seismic Inheritance contributes to this broader goal, demonstrating how interdisciplinary collaboration can support both geoscience communication and the social dimensions of disaster preparedness. [caption id="attachment_12035" align="aligncenter" width="1024"] Attendance at a guided visit given by director and art curator, Ignacio Gutierrez, and seismologist and scientific curator, Sergio Leon-Rios.[/caption]

Virtual visit

Are you interested in the exhibition, but most probably not having an opportunity to visit Chile soon? We invite you for a virtual walk.

Moreover, if you are more like librarian, the catalog with the artpieces and nice photos of the exhibition can be accessed here.

[caption id="attachment_12041" align="alignleft" width="150"] Sergio Leon-Rios[/caption]

About the author
Sergio León-Ríos is Associate Researcher at the Advanced Mining Technology Center (AMTC) at the University of Chile, working on seismology and its applications to mineral exploration. He holds a PhD in Natural Sciences from the Karlsruhe Institute of Technology (KIT), Germany. His research focuses on understanding the physical behavior of active margins, including megathrust earthquakes, crustal fault systems, magmatic fields, and their relationship with the emplacement of natural resources.

Don't Miss the EGU-ST Early-Career Scientist Events during EGU26!

Ezgi Gülay — Mon, 30 Mar 2026 10:55:14 +0000

As the EGU General Assembly (GA) 2026 approaches, the Solar-Terrestrial (ST) Division Early-Career Scientist (ECS) team is organizing various events to give researchers a platform to network with their peers, and strengthen our community! What is ECS? Students (BSc, MSc), PhD candidates and researchers who obtained their highest academic degree in the last seven years are Early-Career Scientists as EGU guidelines indicate. We welcome all ECS to our informal events during the general assembly! You can also find these events on the EGU-GA program page: First browse by session and find 'Community-led' group of events. Here, select 'Pop-up Networking Events' and you will find ours among a variety of other networking events. It might be helpful to deselect all other tags except 'Early Career Scientist (ECS)'. And, if you are interested to join the ECS team to contribute building our community, we would be thrilled to hear from you!

1. Pre-GA ECS Icebreaker

The icebreaker is a joint event organized by Atmospheric Sciences (AS), Geodesy (G), Geodynamics (GD), Natural Hazards (NH), Seismology (SM) and Solar-Terrestrial Sciences (ST) division ECS Teams. This is a great opportunity to get to know ECS from other fields, experience the interdisciplinary nature of geosciences! If the weather allows, we will meet at the Copa Beach near the conference center. You can come by after you pick-up your name badge after 16.30. Feel free to bring your own snack and drinks, but you may also get some drinks at the nearby cafes. The plan is to go to the EGU Opening Reception together starting at 18.30. [caption id="attachment_4393" align="alignleft" width="250"] ECS icebreaker 2025 at Copa Beach[/caption]

Location: Copa Beach (weather permitting) (https://maps.app.goo.gl/WEyvmG7yUb6tjYa19)
Date: Sunday, 3 May
Time: 16:30 – 18:30 CEST

Don't miss this opportunity to meet your colleagues and acclimate yourself to a full conference week!

2. Solar-Terrestrial ECS Picnic / Meet the Experts

Join us in our traditional picnic! This informal picnic is the perfect opportunity to meet your colleagues earlier in the week. And, that is not all! You will also have the chance to meet and discuss with senior scientists in this casual environment! Grab you own lunch and meet us at the X4 foyer! In case of good weather, the picnic will take place at Donaupark, close to the conference venue, in case of bad weather, we will be at Terrace G. [caption id="attachment_2912" align="aligncenter" width="1594"] ST ECS picnic 2025[/caption]

Location: Donaupark (or Terrace G)
Date: Tuesday, 5 May
Time: 12:30 - 13:45 CEST
Meeting Point: At the X4 foyer (either inside or outside where you can easily identify us with from our signs)

3. Solar-Terrestrial ECS Dinner

[caption id="attachment_4389" align="alignleft" width="375"] ST-ECS dinner 2025[/caption] Don't forget to register for the ST-ECS dinner on Wednesday! Build connections with your peers, maybe meet your future collaborators, and more importantly, have fun with your colleagues in this relaxed atmosphere! Due to limited availability, we kindly ask you to register for the dinner in advance (first-come-first-served basis). Please note that the dinner will be at your own expense.

Registration link: https://docs.google.com/forms/d/e/1FAIpQLSfp1ZAfDh-zGZMDwFvoiyJHdrsE-vL3q7RNAuNXrEglyJykVA/viewform
Location: Prater (more details will be send by email to those registered)
Date: Wednesday, 6 May
Time: 18:15-22:00 CEST
Meeting Point: At the X4 foyer (either inside or outside where you can easily identify us with from our signs)

Bonus: Short Course

The short course 'How Are Postdocs Doing? Rethinking the Postdoctoral Experience in Geosciences' is organized by ST researchers targeting the early-career scientists and highlighting the conditions faced by postdoctoral researchers. The course will include data and findings from surveys, and constructive discussions on the postdoctoral experience. For more information: https://www.egu26.eu/session/57870

Location: Room -2.82
Date: Monday, 4 May
Time: 16:15-18:00 CEST

Be a Part of the ST-ECS Team!

If you want to be a part of the ST-ECS team, you can send an email to ecs@egu.eu, or find one of the team members during the GA. We always welcome new members! We can accomplish more when we are many! We are excited to have you join us in Vienna and become a part of the ST-ECS community. Here is to making EGU26 an inspiring and unforgettable experience together! We hope you will have a great week, The ST-ECS Team

Geodesists on Tour: Circumnavigating Greenland by Helicopter

Rebekka Steffen — Mon, 30 Mar 2026 10:00:27 +0000

Greenland, the world’s largest island, has one of the most challenging environments for geodetic measurements. Maintaining GNSS (Global Navigation Satellite Systems) stations here isn’t just about precision - it’s about ensuring data continuity in an area that’s constantly moving. This is the behind-the-scenes story of a 15,000 km journey around Greenland: five weeks of helicopter-based fieldwork, two engineers, a helicopter pilot and, and more challenges than we can count - each one earning us a few extra grey hairs. The perfect combination to make fieldwork become an adventure!

Why do we go on such a mission?

In collaboration with the Danish agency for Climate Data, DTU (Technical University of Denmark) Space operates and maintains the Greenland GNSS Network (GNET). GNET consists of 71 geodetic quality GNSS antennas mounted to bedrock all the way around Greenland. The Network plays a key role in determining bedrock displacement (Glacial Isostatic Adjustment), validation of climate satellite missions, reference network for Greenland, and much more. The oldest station dates back to 1995 with most of the network being established in 2007-2009. The network continuously measures Greenland’s movement. Most of the stations are categorized as remote sites, meaning that we are working with an autonomous running system, running on a battery and solar framework. This is where the problems start: freezing temperatures, high winds, equipment failure and visits by the native wildlife (foxes and polar bears) all contribute to potential downtime of specific sites. That’s the reason why we aim to visit every remote GNET site once a year, during our month-long helicopter-based fieldwork campaign during the summer. [caption id="attachment_5386" align="alignright" width="425"] Overview map of the helicopter flightpath and all visited sites, from the 2025 summer season.[/caption]

The 2025 season

In 2025, the goal of the trip was not only to perform general maintenance and make various updates on all 49 remote GNET sites, but also to install two new GNET and a GNSS-IR specific site in Daneborg. The helicopter trip usually starts in Tasiilaq in Southeast Greenland - with preparation and packing of personal luggage, tools and extra hardware into the helicopter. To be sure that we got everything packed and ready to go, we go for a small roundtrip out from Tasiilaq, to visit our two GNET sites in Isortoq and at Helheim glacier. With the confirmation that we were ready to go, we headed north with the aim of circumnavigating Greenland counterclockwise. A planned roundtrip of roughly 12,000 km of rural remoteness and five weeks in each other’s compagnies. [caption id="attachment_5334" align="alignleft" width="291"] The GNET operational team before taking off (day 1). From left: Tim Nicholaisen – GreenlandCopter, Thomas H. Nylen and Christian Solgaard – both DTU Space. Picture cortesy by Jean-Marie Bärtsch.[/caption]

The beginning

We started at our “base” in Tasiilaq and flew towards the north (remember, counterclockwise). Due to bad weather conditions, we made an unexpected stop just on the southside of Scoresbyssund fjorden. A night filled with excitement followed. With stories that will last a lifetime awaited us, it was with a sigh of relief that we were all still a part of the trip the following day. The coffee and breakfast at Nerlerit Inaat were close to the best I have ever had. However, the weather forecast for Northeast Greenland looked like winter was already back and the whole coast would be in snowstorm conditions for the next 14 days... No flying conditions for a helicopter. So, a decision had to be made: do wewait it out, risking being stuck for two weeks, or do we turn around, go clockwise around Greenland, throw all our planning and months of preparation out the window, and add an additional 2000 km to the journey to get as much done as possible... We chose the second option.

Starting again

Back in Tasiilaq after four days. we started the helicopter mission again, now almost ten days behind schedule. The new ambitious goal was to get from Tasiilaq to Qaqortoq (South Greenland) in one day, then the next day from Qaqortoq all the way up to Kangerlussuaq (KISS) (West Greenland) almost 1/5 of the entire trip in two days. At this point in the trip, we agreed that if we could make it to Pituffik Space Base in Northwest Greenland, then we would call the season a success. The season restarted, and finally it felt like we were making some progress. The weather turned for the better with only two bad days, where we would have to stay grounded. In Ilulissat we had a planned pilot change, and from there we headed further north over Qaarsut, Rink Glacier (which year after year proves to be one of the coldest and windiest places in non-glaciated Greenland), all the way up to Upernavik (Northwest Greenland) and then to Pituffik Space Base (Northwest Greenland). From Pituffik Space Base, we went for our station DKSG; however, the station showed some signs of a visitor. [caption id="attachment_5342" align="alignright" width="409"] Polar bear from the comfort of the helicopter at Daugaard-Jensen Glacier, Northwest Greenland. Picture cortesy by Christian Solgaard.[/caption]

Who visits the station besides us?

Greenland is known for polar bears, and they seem to have a liking for GNSS stations and installations as we usually find some of these stations almost completely chewed up when we arrive for maintenance. So, early in the trip we made it a security practice of flying a few circles with different diameters around our stations when arriving in the field. At this point after roughly 2.5 weeks in the field, we had luckily not encountered any polar bears near our GNET sites. However, our arrival at station DKSG (Daugaard-Jensen Glacier – Northwest Greenland) proved to change those statistics. The station is situated atop of a nunatak (a non-glaciated outcrop surrounded by the icesheet) a few kilometers inland. As we got closer, tracks started to appear in the older snow patches around our station. At closer inspection however the tracks looked weather washed and old, but we chose to do a few extra circles anyway and thank God for that decision! Not more than 2 minutes later we spotted him, a massive polar bear running up a hill less than a kilometer from where our station is located. I guess we found the culprit. Luckily, this time they chose not to check whether a GNSS station is part of a balanced diet. [caption id="attachment_5336" align="alignleft" width="374"] General maintaince on the GNET station HRDG in East Greenland. Picture courtesy by Jean-Marie Bärtsch.[/caption]

Back on track

Once we made our intermediate goal at Pituffik Space Base, it was time to plan the last leg of the trip: from Station Nord to Tasiilaq, which is usually one of the hardest parts of the journey, even with the part usually being at the start of the field campaign. This year, we will have to tackle it after 3.5 weeks. Again, the weather started to become very tricky, so we had to get to Danmarkshavn in a hurry with the plan of staying there at least two days. However, a worsening weather forecast made us work through the evening, such that we could leave right after breakfast the day after. The following morning, we barely escaped. Five minutes after takeoff, Danmarkshavn disappeared into fog with less than five meters of visibility, locked in bad weather for the week. Our plan to stop at Daneborg was abandoned when fog rolled in there as well, sending us directly to Mestersvig. From there, with flying again impossible, we walked out to our remote site accompanied by a retired Sirius dog as our polar bear guard. As we left Mestersvig and headed south to Tasiilaq, we were officially ending this year’s circumnavigation of Greenland. The feelings going through your body, when getting closer to the end of such a long field trip, are indescribable. On the one hand, you can get a feeling of sadness that it’s all coming to an end, and at home there is a desk in an office waiting for you. On the other hand, you are also so so tired of flying and working 15-hour days 7 days a week.

Not only polar bears around

When we arrived at Danmarkshavn, they had had problems with an Arctic wolf, which had been drawn in by the stations' sledge dogs. As we worked in the evening a bit outside the base, in the silent Arctic evening, we heard the wolf howling in the distance, after a day of working in prime polar bear country, it was a very nice change of scenery, that the danger was “just” from a wolf and not a polar bear. It doesn’t take much to get used to the extremes.

Two is not enough

By now, you might think you know all about Greenland’s harsh weather and curious animals. But in the field, surprises come in many other forms too. After two weeks into the trip, we had a medical emergency, which meant one of our team members had to go back to Denmark for treatment (he is okay now) and we were one member short. This left our pilot and me in a bit of a conundrum, firstly we needed a reserve for the remainder of the trip, secondly, how the hell do you get a person from Denmark to North Greenland with a few days warning!? We started working on the logistical problem first, myself in Pituffik and a colleague back at DTU in Denmark. Good contacts in the Joint Arctic Command (JACO) quickly made it possible for us to get a person on the next C-130 flight from Aalborg to Station Nord, the flight was to arrive at Station Nord six days later. Then, finding someone who is able to go on a 2.5 week long fieldwork with a two day warning – luckily we had a colleague on reserve. Now the next challenge was for the pilot and me to get from Pituffik in the west to Station Nord in the east in one day to meet our new companion, a trip that normally takes two days. Four refuelling stops, three GNET stations, and hours upon hours of beautiful scenery found nowhere else in the world than North Greenland, we made it to Station Nord and welcomed our new companion from Denmark. From then on, the three of us tackled the rest of the trip together. [caption id="attachment_5345" align="alignright" width="398"] One of the great benefits of flying around Greenland in a helicopter, is the endless series of beautiful landscapes. Picture courtesy by Christian Solgaard.[/caption] In the end, the expedition members covered around 15,000 km, flying around for 85 hours. We visited all but five remote GNET sites (which in a normal year is more than approved), we told the same jokes around a thousand times to each other in the helicopter and the same stories we told in the beginning were retold at the end. And all of us are returning home to family and normal life, with enough stories to last a lifetime! A season with as many problems and challenges as we have ever had, but still, I for one are already looking forward to the next season, as we do it all over again in the summer of 2026, but hopefully counterclockwise then.

Classroom on Ice: The Patagonian Icefield Research Program

Sophie Berger — Fri, 27 Mar 2026 13:52:47 +0000

An isolated fjord at the edge of the Southern Patagonia Icefield. A small cluster of tents pitched beside Bernal Glacier. Fourteen days without roads, cell reception, or routine – only creaking ice fronts, restless wind, the constant murmur of meltwater, unrelenting rain, and a team of fellow adventurers as companions. The Patagonia Icefield Research Program (PIRP) is an immersive classroom where students and early-career researchers learn directly from the landscape and the glacier itself. This is our adventure diary from the 2025 expedition.

What is the Patagonia Icefield Research Program?

The following story is about a group of early career researchers, faculty, and staff who spent 14 days camping near Bernal glacier in Patagonia. During this time, we learned and practiced a range of fieldwork techniques, including radar surveys, glaciological measurements using ablation stakes, glacier boundaries reconstruction from historical data, and taking sediment cores. We were part of an initiative called the Patagonia Icefield Research Program (PIRP). The 2025 campaign was the fifth in the history of the program and the second one on Bernal glacier; the previous three took place on Grey glacier. The program is run by Dr. Camilo Rada and Natalia Martinez and was originally created to give Master’s students from the University of Magallanes (Chile) hands-on experience working on different glaciological research projects. In the last two years the program was expanded to include applications from students from around the world. The goal of PIRP is to provide a genuine glacier fieldwork experience – raw, unpolished, and both physically and emotionally demanding. Fieldwork in Patagonia means facing nearly constant rain, freezing temperatures, mud, and exhaustion, and even learning to dry wet gear using only body heat, all while carrying out real scientific research. The program brings together students from different nationalities, cultures, and levels of mountain experience, ranging from complete beginners to seasoned adventurers. For most participants, it is also the first time setting foot on a glacier. The individual student projects span a variety of disciplines, from geology and glaciology to science communication, giving each student the opportunity to work on the projects that interest them the most. In 2025, the team consisted of nine faculty mentors and staff and eleven students (Master’s and PhD students) Of these, ten were international, coming from Colombia, Bolivia, the United States, Germany, India, Nepal and Argentina, and the remaining participants were Chilean. Most of the students were Master’s students from Chile and the international students were PhD students.

Preparing for the Adventure

Our story begins in Puerto Natales, Chile, where we spent the first few days in a picturesque guest house called “Casa Raky”. Here is where the national and international students first met each other, along with the faculty mentors and staff. During this time we had many opportunities to exchange experiences and learn about each other’s cultures over shared meals and long nightly conversations as we shared rooms. We also went into town together to buy ingredients and prepare dishes from our different cultures, for example one evening we helped prepare Chai Tea. [caption id="attachment_17285" align="aligncenter" width="694"] Workshops on how to use safety equipment (left) and setting up tents (right). [Photo Credit: Dr. Christina Draeger and Dr. Gwenn Flowers.][/caption]During the days at Casa Raky, we learned how to use the safety equipment required for working on the glacier, how to set up the tents, and practical tips on how to pack our gear. We were also introduced to “leave no trace” principles and the clothes layering system that would help us stay warm and dry in the field. In parallel, everyone began preparing materials for their individual projects or buying any missing clothes or equipment. We stayed two days at Casa Raky because we had to wait for a suitable weather window without too much wind and rain that would allow us to travel safely by boat to the glacier. Patagonia is a place with highly variable weather, where strong winds and heavy rain can appear suddenly and change conditions from one moment to the next. [caption id="attachment_17291" align="alignnone" width="720"] Left) Students,faculty and staff preparing temperature sensors and ablation stakes to measure surface melt. (Right) Students preparing scientific equipment and data for their projects. [Photo Credits: Dr. Gwenn Flowers and Andres Cruz.][/caption]

Journey to Bernal Glacier

After our days of preparation for the field, we were finally ready to head into the field. The glacier where we would be working is called Bernal Glacier, located in the Sarmiento Range below the Southern Patagonia Icefield. Reaching it required a three-hour boat trip. On the way, we could see the beautiful landscape, flora and fauna of the Patagonian wilderness. As we moved deeper into the fjord, glaciers along the mountain range gradually came into view. [caption id="attachment_17292" align="alignnone" width="720"] (Left) Reference map of Bernal Glacier location. (Right) Zamudio Glacier, one of the glaciers in Sarmiento Range, which we saw from the boat on the way to Bernal Glacier.
[Photo Credits: Jose Zambrano (map) and Andres Cruz (photo)][/caption]The boat trip ended when we arrived at a remote beach and started unloading equipment and provisions from the boat. Once everything was on shore, we were paired to share the available tents. The camp was set up in the nearby forest and we pitched our tents on wooden platforms that Camilo and Natalia had built to keep them from possible flooding and started unpacking our backpack. This was the moment when the real adventure started. [caption id="attachment_17294" align="alignnone" width="655"] (Left) Tent where Javier and Andres stayed. (Right) Students help load equipment onto the boat for the journey to Bernal Glacier. [Photo Credits: Andres Cruz][/caption]

Patagonia as a Classroom

The first week at camp was packed with workshops designed to teach us how to use the various instruments and techniques required for glacier research, covering both practical skills and theoretical knowledge. The workshops were done at different places, some at the camp but most of them in the proglacier zone and on the glacier, which meant carrying all the necessary heavy equipment with us, including ice augers, a hot-water drill, sediment core extractor, and our safety gear. As the glacier landscape is constantly changing, a path that had been usable last year was now completely blocked due to glacier retreat, forcing us to take a longer, more challenging route that involved crossing rivers, navigating slippery rocks, and scaling the side of a mountain. [caption id="attachment_17295" align="alignright" width="300"] Students and faculty members during the glacier travel and ice climbing workshop, where we learned how to use ice axes and practiced basic climbing techniques on ice. [Photo Credits: Andres Cruz.][/caption]On the glacier, one of the most memorable workshops was the hands-on session where we learned how to use the instruments required to drill into the ice – both manually and with hot-water drilling systems – to install ablation stakes. Bernal Glacier has complex and very steep topography, and some groups working farther up the glacier needed to climb sections of ice to reach their study sites. For this reason, we also had an ice climbing workshop along the glacier’s vertical walls. For most of us, this was the first experience climbing an ice wall. Despite the demanding approach and complex glacier terrain, these experiences were some of the most rewarding parts of the expedition, giving us a true sense of what working in glacier research really entails.

Time to do some Measurements

During the second week, we put our training into action, diving into our projects under the guidance of the faculty mentors. Each student worked on an individual project while collaborating and supporting one another across teams. Some teams focused directly on the glacier, for example, by measuring surface melt and daily ablation at different points using stakes. [caption id="attachment_17301" align="aligncenter" width="682"] (Left) Workshop on drilling holes with an ice auger to install ablation stakes. (Right) Dr. Gwenn Flowers showing how to use the manual ice auger.
[Photo Credits: Andres Cruz.][/caption] They also studied how ice albedo – how dark or light the ice is – and debris cover affect local melt rates. Other teams mapped supraglacial rivers and analyzed water flow, and another used ground-penetrating radar to examine ice thickness. Teams in the proglacial environment focused on studying the landscape and processes beyond the ice itself. They collected cosmogenic samples from different glacier erratic blocks to understand the glacier’s history, conducted bathymetric surveys to map lakes, captured drone imagery for geodetic mass balance, and sampled river sediments to analyze material transported by meltwater. Another project focused on science communication, developing interpretive sign displays for tourists that visit the glacier, explaining the environment, glacier dynamics, and climate change. They also reconstructed historical images and timelines to illustrate the glacier’s evolution over time. The projects were truly diverse, and evening debriefings offered an exciting opportunity to share insights and learn from each other’s work.

[caption id="attachment_17303" align="alignnone" width="661"] Photos of the students working on their projects with support from faculty and staff.
From top to bottom and from left to right: 1) Nadia Cohen conducting a radar measurement of the thickness of the glacier.2) Gabriela Quispe with Dr. Gino Casassa setting up subaquatic ablation stakes to measure the melt rates where the glacier extends into the proglacial lake underwater. 3) Jose Zambrano, Anuska Pudasaini and Dr. Rodrigo Soteres drilling the exposed glacier’s bedrock to install temperature sensors. 4) Dr. Christina Draeger and Rebeca Fernandez taking wind gust measurements[/caption] [caption id="attachment_17306" align="alignnone" width="678"] 5) Pedro Granovsky and Dr. Camilo Rada installing a Global Navigation Satellite System (GNSS). 6) Javier Norambuena and Jose Zambrano taking rock samples for cosmogenic analysis. 7) Jose Zambrano and Natalia Martinez conducting bathymetric measurements.
[Photo Credits for photos 1 though 7: Javier Norambuena, Anuska Pudasaini, Dr. Gino Casassa, Andres Cruz, and Dr .Gwenn Flowers.][/caption]

Sharing our experiences with the Puerto Natales community

With heavy hearts (and backpacks) we sadly saw that our days in the camp had come to an end. We packed our equipment and prepared for the same trip that we had taken 14 days earlier to return to Puerto Natales. After taking the first shower in a few weeks, we went out to celebrate the end of the field experience with a special Patagonian dish, a lamb, prepared just for us. [caption id="attachment_17308" align="alignnone" width="720"] (Left) Faculty, staff and students celebrating the end of the expedition. (Right) Students working on their project data in preparation for the final presentations.
[Photo Credits: Navneet Singh and Dr. Camilo Rada.][/caption]The end of the expedition was not only about eating lamb, resting, and enjoying the city. As we arrived, the students started processing the data collected in the field and preparing slides for the final presentations. The program concluded with a public presentation for the Puerto Natales community at Mulato Cafe, where the students shared some of their results and their experiences during the days spent at camp. The event had a good turnout and the audience was very enthusiastic about listening to our adventure. The international students were brave enough to give their presentations in Spanish (after only two days of practice!). [caption id="attachment_17311" align="alignnone" width="646"] (Left) PIRP faculty and staff (from left to right: Dr. Camilo Rada, Diego Gamonal, Dr. Rodrigo Soteres, Dr. Gwenn Flowers, Natalia Martinez, Yara Vargas, Dr. Christina Draeger, Dr. Gino Casassa and Ignacio Nuñez) (Right) Navneet Singh during his project presentation at Mulato Cafe.
[Photo Credits: Navneet Singh][/caption]

Reflections

Bernal Glacier was more than a research site: it became a temporary home where students from around the world gained technical skills, resilience, adaptability, and practiced their ability to work together in demanding conditions. The challenges, teamwork, and rapidly changing environment created unforgettable memories and lessons. As feedback, we heard from many students that the experience was truly transformative. It is incredible what Camilo and Natalia have built with this program. They brought mountains of equipment and spent countless hours meticulously planning the trip. They constructed wooden platforms for tents, cleared paths, and even built a Tyrolean bridge to safely cross the river. Their dedication and love of learning set an inspiring example for all of us. We hope you enjoyed reading our diary as much as we enjoyed writing it and remembering about this awesome experience. We know that if some of the friends we made during the program read this blog, they will probably say that we miss too many details and funny anecdotes. And they would be right, but we preferred to just give a brief glimpse, so that future students can discover it for themselves without too many spoilers. We hope that this post encourages you to take a look at the summer school and maybe even decide to spend a few weeks in Patagonia. PIRP also offers some funding possibilities to help students participate, so make sure to take a look here. We hope to see you soon in Patagonia! [caption id="attachment_17314" align="alignnone" width="1600"] Bernal Glacier and the main river.
[Photo Credits: Javier Norambuena][/caption]A big hug and a special mention to all the people who made this adventure possible: Directors: Dr. Camilo Rada, Natalia Martinez. Faculty members: Dr. Gino Casassa, Dr. Rodrigo Soteres, Dr. Gwenn Flowers, Dr. Christina Draeger. Staff for logistics, safety and mountaineering: Yara Vargas, Diego Gamonal. CONAF park ranger: Ignacio Nuñez Students: Sandra Barrera, Rebeca Fernandez, Gabriela Quispe, Pedro Granovsky, Anuska Pudasaini, Navneet Singh, Nadia Cohen, Javier Norambuena, Paula Silva, Jose Zambrano, Andres Cruz.

Edited by Mirjam Paasch, and Mack Baysinger

How atmospheric circulation patterns high above the Southern Ocean influence the deepest layers of the global ocean

Jacqueline Behncke — Fri, 27 Mar 2026 10:48:55 +0000

The ocean surrounding Antarctica plays a crucial role in the climate system. Along parts of the Antarctic coast, very cold and salty water becomes dense enough to sink all the way to the ocean floor. This process forms Antarctic Bottom Water: the deepest water mass in the global ocean, representing about 40% of its total volume. As this dense water sinks into the abyss, it helps trap heat and carbon at depth and supplies oxygen to the deepest layers of the ocean.

Dense Water Formation at the Antarctic Margins

Dense water formation around Antarctica occurs mainly in coastal polynyas, which are wind-driven, recurring openings in sea ice. These exposed ocean areas lose heat rapidly to the cold atmosphere, promoting sea ice formation. As ice forms, salt is released into the surrounding water, increasing its density. The resulting dense water sinks off the continental shelf, cascades down the continental slope, and eventually contributes to the renewal of abyssal waters. [caption id="attachment_3377" align="aligncenter" width="500"] Figure 1: From Morrison et al. (2020): Dense water forms on the Antarctic continental shelf, in four main regions. It then cascades down the continental slope and sinks into the abyss.[/caption] Observations indicate that Antarctic Bottom Water formation has declined in recent decades, and models project this decline to continue. Yet the drivers of year-to-year variability remain poorly understood.

The Zonal Wave-3 Mode: A Potential Driver

One possible source of variability is the Zonal Wave-3 (ZW3), a mode of atmospheric circulation characterized by three alternating high- and low-pressure systems encircling the Antarctic continent. The longitudinal position of these systems can shift, changing the phase of the ZW3 and altering the direction and strength of north–south winds over the Southern Ocean. The ZW3 has been shown to explain anomalies in winter sea ice extent, as it can displace the sea-ice edge northward or southward depending on its phase. It is therefore a strong candidate for driving variability in dense water formation, by enhancing or supressing polynya activity at the Antarctic coast.

Modelling the impact of ZW3

[caption id="attachment_3347" align="aligncenter" width="500"] Figure 2: Two phases of Zonal Wave-3 like atmospheric perturbations (top) and their winter sea ice response (bottom).[/caption] In our recent study (Auger et al., 2023), we explored how this atmospheric pattern could influence dense water formation using a set of ocean–sea ice model experiments. In each experiment, we imposed a different phase of the ZW3 pattern, effectively shifting where its wind anomalies occur around Antarctica. This allowed us to isolate how large-scale changes in winds affect coastal sea ice production and the export of dense water to the deep ocean. The simulations reveal that strong ZW3 events can influence dense water formation and export for several years. The effect is especially pronounced in key formation regions such as the Weddell Sea and the Ross Sea. Depending on where the high and low-pressure systems are positioned, the ZW3 can either boost or suppress dense water formation. In some cases, production nearly doubles. In others, it is greatly reduced, even provoking a halt in dense water export to the abyss over several years. The impacts often work in opposite directions across regions: when formation increases in the Ross Sea, it tends to decrease in the Weddell Sea, and vice versa. [caption id="attachment_3349" align="aligncenter" width="1024"] Figure 3: Simulated response of dense water formation to the perturbations shown in Figure 2, for each formation region.[/caption]

Implications

Our results highlight an important link between large-scale atmospheric circulation and deep ocean processes. Because Antarctic Bottom Water connects the surface climate to the deepest ocean layers, understanding how atmospheric variability controls its formation is essential for anticipating long-term changes in the global climate system.

Communicating and Managing Residual Risk with Perfect Storms and Other Counterfactual Stories

Christina Orieschnig — Thu, 26 Mar 2026 09:00:20 +0000

The aim of risk management is to prepare society in order to limit loss and damage when an extreme event occurs and to restore the functioning of society afterwards . While current risk management practices are helpful in many regards, they fall short when it comes to unprecedented events. An analysis of event pairs and recent disasters show that societies often fail to cope with events that are larger than what they have experienced or what they can imagine. (Flood) risk analysts have argued again and again that risk assessment and management should encompass the entire range of events, from frequent events to very rare events, and even the worst-case scenario. However, this plea is not heard. Why? One part of the answer is of a psychological nature. Humans are bad at thinking outside their experience. Psychologists have identified a large suite of cognitive biases that humans fall prey to. One of them is availability bias: Confronted by the (difficult) question of assessing the probability of an event, we tend to answer another (much easier) question: How easily can I recall or imagine such an event?

How to Imagine Extreme Events

Thus, we underestimate the probability of events that we have not experienced, but overestimate their probability as soon as we have seen them. How to overcome this unwillingness to think and to prepare for unprecedented events? We need stories that speak to people. Presenting the 1,000-year flood or the worst-case scenario does not help much here. Counterfactuals - past events that could have occurred - seem like a good tool to develop such stories. In a previous blog post, Paul Voit has discussed spatial counterfactuals; here the idea is to shift a recent rainfall event in space and quantify what the consequences would have been. Even small shifts can lead to dramatically larger flood peaks and consequences. The story behind this is simple: This time you have been spared from havoc, but look what could have happened if the rainfall had fallen only 15 km further to the east! There are many ways to construct counterfactuals. We have used the Perfect Storm analogy to develop unprecedented, but plausible flood events.

Introducing Perfect Storms

This term became famous through the movie ‘The Perfect Storm’, directed by Wolfgang Petersen, which refers to a storm in 1991 characterized by an extraordinary combination of weather conditions that created a catastrophic situation for a fishing community in Massachusetts. More generally, the Perfect Storm metaphor describes a situation where several adverse factors come together to produce a disastrous outcome. In our case, we recombined historically observed extremes in precipitation and soil moisture to generate new flood scenarios. In this way, we produce events whose severity and damage can strongly exceed those of the observed events. While our Perfect Storm approach is limited to event rainfall and antecedent catchment conditions, it is (conceptually) straightforward to include additional factors, such as breaching of flood protection or failure of evacuation. We feel, and our discussions with practitioners support this, that tweaking a recent (important) event is something that lay people can much more easily understand compared to a more technical approach, such as the 1,000-year flood.

How Perfect Storms Can Help Prepareness

If we accept that such events are easier to communicate: What to do with them? They are not associated with a probability, and they are not helpful for cost-benefit analysis. And we cannot build protection measures that high. However, there are many measures that are worth thinking through on the basis of such scenarios. For example, we can use them for disaster management training and awareness campaigns. One of the problems during the Western European floods in July 2021, with 240 fatalities, was that both, laypeople and experts, did not believe that the flood could be that severe. Many people died not because they didn’t receive a warning, but because they started with mitigation measures, for example going down to the basement to secure assets. Another approach is to use them to identify hotspots of sensitive and critical infrastructure. A local inundation can have widespread network effects - flood-proofing key network elements can decide whether a local disruption spreads excessively or not. Or we can use them to design fail-safe systems; systems that fail in such a way that the damage is minimized. In view of increasing climate extremes and changes in vulnerability and exposure, we need to put more emphasis on unprecedented events. Perfect Storms and counterfactuals are worth exploring as a basis for communicating risk and for identifying risk reduction measures beyond technical protection.

Meet Corinne Le Quéré - Vladimir Ivanovich Vernadsky medal winner 2025

Franziska Lechleitner — Wed, 25 Mar 2026 17:44:02 +0000

We spoke to Corinne Le Quéré, a Royal Society Research Professor of Climate Change Science at the University of East Anglia (UK). She is the recipient of the 2025 Vladimir Ivanovich Vernadsky medal of the EGU, awarded annually by the Biogeosciences division to those who make an exceptional contribution to biogeosciences.

Can you tell us a bit about your background and how your career progressed to your position today?

It took me a little while to find my way but eventually, after a year of studying anthropology, I did my undergraduate in physics at the University of Montreal and my master's in atmospheric and oceanic sciences at McGill University. I then worked for four years as a professional technician at Princeton University, where I learned to model the ocean carbon cycle, before completing a PhD at the Sorbonne University in Paris, also on carbon cycle modelling. From there, I moved to the Max Planck Institute for Biogeochemistry in Jena, Germany, and eventually obtained a faculty position at the University of East Anglia in the UK. I also worked in parallel at the British Antarctic Survey for five years before becoming Director of the Tyndall Centre for Climate Change Research. It was around that time that I started the Global Carbon Budget within the Global Carbon Project, which I directed for thirteen years.

More recently, I became increasingly interested in informing policy. I became a member of the UK Climate Change Committee and eventually was invited to found and direct the French equivalent, the Haut conseil pour le climat until 2024. I remain at the University of East Anglia today, as a Royal Society Research Professor in the School of Environmental Sciences.

You have initiated and co-led the Global Carbon Budget within the Global Carbon Project, with the goal of providing an annual synthesis of global emissions and sinks of carbon. What do you think has been the most important insight for science and for society from this effort?

For science, the Global Carbon Budget has been fantastic because it provides a pathway by which the community comes together every year, synthesises the latest information, and confronts evidence from different sources - observations, models, and increasingly machine learning approaches alongside process-based models. This synthesis and the challenging of information from diverse sources have allowed us to identify the frontier of understanding in the global carbon cycle, both on land and in the ocean.

For society, the annual release of information timed with the UN Climate Change Conferences (Conference of the Parties - COP) has maintained crucial momentum and visibility for climate action. It brings the latest trends at the forefront of the policy conversation when it matters most.

Coming from a climate and carbon cycle modeling background, what has been your biggest eye-opener when moving into the climate policy space?

My biggest eye-opener has been realising that most policymakers working in this field genuinely want to act on climate change, and they are well equipped to take decisions under uncertainty, it's their job. This has encouraged me to be more present in the policy space, even though that has meant I spend a lot of time outside my comfort zone, and to ensure that the information I produce is understandable, accessible, and actionable. I don't always agree with the actions that are ultimately taken, of course, but I've come to respect that the obstacles are real and many decision makers are trying hard to make climate responses work, at least in the countries where I've operated (mainly the UK and continental Europe).

Where do you see your field of research progressing in the future, and what are the knowledge gaps to be filled?

Key gaps to be filled include understanding how the land and ocean carbon reservoirs respond to a changing climate. For the land, it's particularly important because we observe variability in atmospheric carbon dioxide on timescales of three to ten years, which we suspect is attributable to the terrestrial biosphere's response to climate change, yet we cannot fully explain it today. Understanding this response is crucial because it will influence how the biosphere responds to future climate change and potentially increase projected warming.

For the ocean, the situation is somewhat different. We have a much better quantitative understanding of the ocean carbon sink and its variability. The real issue is how marine ecosystems will evolve in a changing climate under multiple stressors - ocean acidification, deoxygenation, fisheries pressure, microplastics, and more. If ocean productivity declines, it could have significant consequences not only for the availability of marine resources, but also for the long-term storage of carbon in the deep ocean and, consequently, for the zero emissions commitment.

If you were able to travel back in time and give your younger self one piece of advice, what would it be?

I would tell my younger self not to worry so much, and to pursue the research I truly value and believe is important. I'd also encourage myself to engage with society outside of science, to step out of academic circles and understand how the issues that I research matter beyond the research community. Beyond that, I'd emphasise valuing progress over the end goal. When you have ideas and move them forward, you often generate new ideas in the process. You see the research, the problem, and even the world from a different perspective. That shift in perspective is incredibly valuable in itself.

Finally, what does it mean to you personally to have been awarded the Vladimir Ivanovich Vernadsky medal?

This medal means a great deal to me. It recognizes not only my own work, but also the immense support from my research group and the precious and productive collaborations from which I have benefited over the years. I feel very lucky to work in this stimulating field, to interact with people from around the world, and to have the opportunity to make a difference.

EGU Campfire Geodesy – Share Your Research – 18th Edition

Marius Schlaak — Wed, 25 Mar 2026 17:28:12 +0000

We are excited to announce the 18th edition of Geodesy Campfire – Share Your Research in April. The Geodesy EGU Campfire Events “Share Your Research” give (early career) researchers the chance to talk about their work. We have two exciting talks by our guest speakers, David Rodríguez Collantes and Klara Middendorf. Below, you can find the details of the topics awaiting us. We will have time to network after the presentations. Please join us on Zoom on 16th April 2026 from 13:30 to 15:00 (CEST). Register for this webinar here. David Rodríguez Collantes @Royal Institute and Observatory of the Spanish Navy:

Current projects and work carried out in the Geophysics Section of the Royal Institute and Observatory of the Spanish Navy.

Lieutenant David Rodríguez Collantes is currently the Head of Seismology and GNSS at the Royal Institute and Observatory of the Spanish Navy (ROA). His current areas of research focus on the analysis of GNSS signals applied to geophysics, including the study of the Eurasia-Nubia convergence zone, seismology, Precipitable Water Vapour (PWV), space weather, and the prediction of geophysical phenomena. He has also collaborated with the ROA's SFEL Laser Telemetry Station. Klara Middendorf @HafenCity University Hamburg, Geodesy and Geoinformatics:

Benefits of future satellite gravimetry missions for characterizing extreme wet events in terrestrial water storage.

Klara is a PhD student at the HafenCity University Hamburg (Germany). She is working on evaluating global coupled climate models using satellite gravimetry observations of terrestrial water storage. Her research focuses on the analysis of hydrological extreme events in models and observations on a global scale, and assessing the ability of current and future satellite missions to detect such extremes. [caption id="attachment_4753" align="alignleft" width="293"] Image credit Baptiste Gombert (distributed via imaggeo.egu.eu)[/caption] Time to connect! After the presentations, we invite everyone in the audience to turn on their camera and microphones, if possible. Participation via the chat is of course also possible. We will start with a short introduction round to get an idea of who is in the room. So if you like to, you can already think about how to summarise your research in a few words so that mortals can also understand it! We’re also open to hear about your favourite dinosaur, your latest burnout, or the 4th element on your tasks list today. Just be there and be talking, we guarantee for the awkwardness. We are always looking for speakers for upcoming Geodesy EGU Campfire Events “Share Your Research”. Are you interested in giving a talk? Then, please express your interest by filling out this form. If you have any questions about the Geodesy EGU Campfire Event, please contact the Geodesy ECS Team via ecs-g@egu.eu. We look forward to seeing you at the Campfire!

Interview ECS GD Awardee 2026 – Sia Ghelichkhan

Editorial Team 2 — Wed, 25 Mar 2026 09:00:06 +0000

The Division Outstanding Early Career Scientist Awards highlight exceptional scientific contributions made by an Early Career Scientist in the fields of Earth Sciences associated with each division. This year, the prestigious recognition for the Geodynamics Division has been awarded to Dr. Sia Gelichkhan, from the Australian National University. Today we have the pleasure of interviewing him on his research, achievements, and perspectives on the challenges and innovations shaping the future of Geodynamics.

[caption id="attachment_42560" align="alignleft" width="347"] Siavash (Sia) Ghelichkhan is a geodynamicist at the Research School of Earth Sciences, Australian National University, where he joined as faculty in 2024. Originally from Iran, he studied theoretical physics before moving to Munich, Germany, where he completed both a Masters in Geophysics and a PhD in Geodynamics at LMU Munich and the Technical University of Munich. He moved to Canberra, Australia in 2019. His research focuses on applying numerical and inverse methods to geodynamics, with a particular emphasis on adjoint-based approaches for reconstructing mantle flow in space and time. He is a lead developer of G-ADOPT (gadopt.org), a computational platform for inverse geodynamics. As an Australian Research Council DECRA Fellow, he is currently working on G-PREM, a three-dimensional dynamic reference Earth model for the Cenozoic, aimed at understanding the mantle's influence on past sea level. Since 2024, he is also a Fellow of the Institute for Water Futures at ANU, where he is developing inverse models of groundwater systems across Australia and globally. More at sia-g.com.[/caption]

"***Recognition like this is not just about the science; it is an* *acknowledgment that none of it happens alone.***"

How would you describe your research in a nutshell?

My research is about turning Earth science observations into quantitative understanding. Over the past few decades, the volume of data describing Earth's interior has grown enormously. New seismic tomography models appear every year, theoretical models and laboratory measurements of material properties have become increasingly precise, and our theoretical frameworks have matured alongside them. But data alone is not knowledge. The central question I work on is: how do we systematically assimilate these diverse observations into physically consistent models of how the Earth works? The methods I develop are rooted in adjoint-based data assimilation: techniques that allow us to optimise the parameters of computationally expensive simulations against observational constraints. What are the rheological properties that best explain what we observe? What is the evolutionary trajectory of the mantle that is most consistent with the available data? These are inherently inverse problems and solving them at the scale and complexity of real Earth systems demands purpose-built computational tools. These ideas did not begin in a vacuum. The foundations were laid during my PhD at Ludwig-Maximilians-Universität (LMU) in Munich, where I was fortunate to be part of a community that had pioneered the formal use of data assimilation in mantle convection and seismic tomography. That environment, shaped by my PhD supervisor and by colleagues whose early work on adjoint methods in geodynamics opened the field, gave me both the technical grounding and the scientific conviction that this approach could be taken much further. It was later, during my postdoc at the Australian National University (ANU), guided by my postdoctoral supervisor, that these ideas matured into the framework and ambition behind G-ADOPT. [caption id="attachment_42563" align="alignright" width="326"] Figure 1 The G-ADOPT logo illustrates the platform's central ambition: applying data assimilation across Earth's systems and timescales. From reconstructing the thermal evolution of the mantle over millions of years, to modelling the solid Earth's response to ice sheet loading and its imprint on sea level, to optimising subsurface flow models against borehole and gravity observations in groundwater systems: the same adjoint-based framework connects them all. (see g-adopt.org).[/caption] That need led to G-ADOPT: the Geoscientific ADjoint Optimisation PlaTform. An open-source framework developed collaboratively by our team at ANU (see gadopt.org and this EGU blog for more). G-ADOPT makes these inversions accessible and reproducible. We have demonstrated its applicability in mantle convection and glacial-isostatic adjustment of Earth’s surface, and we are now extending it to groundwater systems where we are building models of aquifers by assimilating observations from satellite geodesy and borehole data. The underlying ambition is general: to build data-constrained models (what some now call digital twins) of different Earth systems, models that are constrained by what we have actually observed. Why does this matter? Consider the expected sea-level rise due to climate change. Arguably one of the defining scientific and societal questions of our century. To understand where sea level is going, we look to the geological past: Pliocene shorelines as a proxy of similar green-house concentrations in the atmosphere by the end of this century, glacial cycles, the ongoing rebound of formerly ice-covered land. But every one of those records carries the fingerprint of the solid Earth. A mid-Pliocene sea-level marker does not simply record how much water was in the ocean; it has been moved up or down by dynamic topography driven by mantle flow over millions of years. The present-day rate of relative sea-level change at any coastline reflects the viscoelastic response of the mantle to the last and current deglaciation. These are not small corrections: they can dominate the signal. Disentangling them is not a problem that will be solved once and set aside; it is an ongoing scientific journey, where each answer reveals new layers of complexity. Our methods and tools are designed for exactly that kind of problem: one that demands sustained, rigorous integration of observations, physics, and computation.

What was your reaction to the news that you had been awarded the ECS Division Award?

Honestly, my first feeling was one of deep relief. A sense that the work had been seen. Much of my day-to-day effort goes into the quiet, unglamorous work of developing numerical methods, and building computational infrastructure. Work that does not always translate neatly into the kind of results that catch the eye at first glance. So, to have this recognised by the community meant a great deal. But what followed almost immediately, and what has stayed with me since, is gratitude. Not in the abstract. Gratitude that is directed at specific people. The senior scientists who shaped how I think about problems. The junior researchers and students whose questions and ideas have sharpened my own. Our team, the observational and computational Geodynamics group at ANU, who have put enormous effort into building something together. This award belongs to all of them as much as it does to me. I should also say: the news arrived during what has been one of the more demanding chapters of my life: balancing the responsibilities of a faculty position with being a parent to a young child. When I heard, I thought immediately of the sacrifices my family and the people around me have made to make everything possible. Recognition like this is not just about the science; it is an acknowledgment that none of it happens alone.

What kind of impact do you hope your work will have in the field or in the broader community?

The impact I hope for operates on two levels. The first is practical: by providing open, well-documented tools to the community, I want to make the kind of integrated, observation-constrained modelling of Earth systems that was once considered aspirational into something that is routine. Not just for our own research group here at ANU, but for anyone working on these problems. The best tools are the ones that outlive the projects that created them. The second level is more about how we think. My conviction is that none of the questions that matter most, e.g., where sea level is heading, how we secure and manage groundwater resources, how we find critical minerals, how we understand past climate states, can be answered without geodynamics. The forces that drive mantle flow, reshape the surface, and govern the solid Earth's response to loading are not a niche concern; they are woven into almost every Earth science question, whether or not we choose to acknowledge them. In a sense, we in Earth Sciences, are all geodynamicists! We are all, ultimately, interested in force balances and the dynamic processes that shape our planet. What I hope to achieve, over the long arc of a career (hopefully!), is to help dissolve the artificial boundaries that still fragment Earth sciences. The mantle does not know that we have organised ourselves into separate departments. Neither does groundwater, or the ice sheets, or the coastlines recording sea-level change. The ambition behind our tools and methods is to be able to look at any of these systems, assimilate the observations that constrain them, and build coherent, data-disciplined models - digital twins, if you like - that reflect the Earth as it actually is: coupled, dynamic, and whole. [caption id="attachment_42564" align="aligncenter" width="650"] Figure 2- Building a digital twin of Earth's mantle. The present-day thermal structure of the mantle (rightmost panel) is derived from the REVEAL full-waveform seismic tomography model (Thrastarson et al., 2024) and converted to temperature using the SLB24 thermodynamic framework for mantle minerals (Stixrude & Lithgow-Bertelloni, 2024). This observed temperature field serves as the optimisation target. Using G-ADOPT's adjoint-based data assimilation framework, an optimal initial temperature field at 10 Ma is recovered such that, when the mantle convection equations are solved forward in time, the simulation reproduces the observed present-day state. The sequence (left to right) shows this forward evolution from 8 Ma to the present day. The close agreement between the simulated present-day field and the tomographically derived target demonstrates that the framework can recover a dynamically consistent evolutionary trajectory of the mantle. We are now working towards extending this to the full Cenozoic to produce a data-constrained digital twin of Earth's mantle evolution over the past ~60 million years.[/caption] In your opinion, what will be the future of geodynamics?

In my view, the answer is straightforward: the future of geodynamics is data-driven. Sooner or later, and perhaps sooner than many expect, solving the forward problem will become routine. The advances in numerical methods, computational power, and software infrastructure are converging to make that inevitable. When that happens, the defining challenge will no longer be whether we can simulate mantle convection or glacial isostatic adjustment at sufficient resolution. It will be whether we can systematically assimilate the observations we have been collecting across every branch of Earth science and integrate them within a dynamic reference frame.

That is where the field is heading, and it changes everything. In a truly data-driven geodynamics, observations are no longer confined to the subdiscipline that collected them. Past ice sheet reconstructions carry direct consequences for the rheology of the mantle beneath them. A prediction of sea-level change in the Pacific by the end of this century becomes inseparable from how we understand periods of uplift and denudation in Southern Africa, because the same mantle system connects them. The physics does not respect our disciplinary boundaries, and our methods should not either.

The future, I believe, belongs to frameworks that produce models which are globally consistent, dynamically coherent, and honest about their uncertainties. That is the geodynamics I want to help build.

What advice do you have for early-career researchers who would like to continue their careers in geodynamics? Honestly, I am not sure I am in a position to give advice. I still learn constantly from the talented early-career colleagues around me. But if I could go back and say something to myself in the first year of my PhD, it would be this: focus on what matters and try not to be distracted by the noise. In geodynamics, as in any field, there can be pressure to chase short-term outcomes: the next publication, the next metric, the next deliverable. That pressure is real, and I do not want to pretend it can simply be ignored. But the work that endures, the work that I have found most rewarding, has always come from staying close to the fundamental science, from asking questions because they are genuinely interesting, not because they are strategically convenient. The problems worth solving in geodynamics are deep and long-lived. They will still be there when the noise has passed. And of course, like most things in life, it is about balance. Protect the time for curiosity, but do not be naive about the realities of a career. If I have learned anything, it is that the two are not as incompatible as they sometimes feel.

References:
[1] Thrastarson, S., van Herwaarden, D. P., Noe, S., Josef Schiller, C., & Fichtner, A. (2024). REVEAL: A global full‐waveform inversion model. Bulletin of the Seismological Society of America, 114(3), 1392-1406. https://doi.org/10.1785/0120230273
[2] Stixrude, L., & Lithgow-Bertelloni, C. (2024). Thermodynamics of mantle minerals–III: the role of iron. Geophysical Journal International, 237(3), 1699-1733. https://doi.org/10.1093/gji/ggae126

China’s Hainan Unlocks Mysteries of Heat and Sodium Transport 80–100 km Above Earth

nadjaomanovic — Tue, 24 Mar 2026 12:49:26 +0000

When we gaze at the sky, our eyes often linger on blue horizons, floating clouds, or twinkling stars—rarely do we think about the critical processes unfolding 80 to 100 km above ground. This region, known as the mesopause, acts as a vital transition zone for aviation and aerospace activities (not vital for routine commercial aviation, but it is indispensable for high-altitude aerospace, experimental aviation, spacecraft re-entry/launch, and the broader atmospheric models that underpin all aviation operations), where subtle changes in temperature and wind can shape global atmospheric circulation. Now, a team from the University of Science and Technology of China (USTC) has used a cutting-edge sodium lidar in Hainan (19°N, 109°E, Figure 1) to reveal, for the first time, the seasonal variations of gravity wave-driven heat and sodium fluxes in this poorly understood low-latitude region.

A High-Precision "Eye" on the Upper Atmosphere

To explore the mesopause, the team developed a narrowband sodium lidar—an advanced remote sensing tool that uses laser light to probe atmospheric properties. Operating at a wavelength of 589 nanometers, this system features state-of-the-art laser frequency-locking and real-time monitoring technology, achieving an impressive frequency stability of 0.5 megahertz (RMS). This precision ensures accurate measurements of sodium atom density, temperature, and vertical wind in the upper atmosphere. The lidar consists of three core components: a transmitter that emits pulsed laser beams, a 1-meter diameter telescope that collects backscattered photons from atmospheric sodium atoms, and a signal processing module that converts photon counts into scientific data. Since February 2024, the system has operated continuously, accumulating over 326 hours of valid observations—laying the groundwork for groundbreaking insights.

Key Discovery: Double Peaks and Low-Latitude Uniqueness

The team’s analysis yielded a series of remarkable findings, centered on the dual dynamics of heat and sodium transport. The annual average vertical heat flux over Hainan shows two distinct downward peaks: -1.21 K m s^-1 at 89 km and -1.38 K m s^-1 at 92 km. This dual-peak structure contrasts sharply with mid-latitude sites like Hefei (China), where a single peak dominates. The divergence of these heat fluxes drives a cooling rate of approximately 95 K day-1 between 82 and 97 km—comparable in magnitude to radiative cooling—highlighting gravity waves as key regulators of the mesopause’s thermal balance (see Figure 2). [caption id="attachment_1943" align="aligncenter" width="1274"] Figure 2: Monthly mean of nightly mean temperature observed by (a) lidar and (b) SABER. Taken from Wang et al. (2026, AMT, 10.5194/amt-19-1629-2026), their Figure 10.[/caption] Sodium atoms serve as natural "tracers" for atmospheric motion. The observations revealed sodium flux peaks exceeding -65 m s^-1 cm^-3 at 92 km, leading to a maximum net sodium loss of 75 cm^-3 h^-1 near 93 km. Notably, Hainan’s sodium flux magnitude falls between those of mid-high latitude stations and Hawaii’s Maui (20.7°N), reflecting the unique dynamical characteristics of low-latitude air circulation. Crucially, the lidar data aligns closely with measurements from the SABER satellite. For example, temperatures below 95 km peak in May and November, with seasonal trends matching satellite observations—validating the reliability of the lidar’s results.

Why this matters

The mesopause is a critical interface between Earth’s middle and upper atmosphere, where gravity wave activity, material transport, and energy exchange shape global circulation and space weather. Although the mesopause, located 80-100 kilometers above the ground, is far from us, its cooling effect will affect the global atmospheric circulation on the ground through a series of chain reactions: The cooling here is caused by gravity waves propagating upward to this region, breaking, and releasing energy. This energy does not disappear out of thin air; it transmits momentum downward to the stratosphere, first accelerating the high-altitude winds in the stratosphere. The stratosphere is closely connected to the troposphere (the atmospheric layer where we live), so the winds in the stratosphere will further drive and change key atmospheric circulation systems in the troposphere, which are the core drivers of surface storms, monsoons, and the movement of cold and warm air. Meanwhile, the strong cooling at the mesopause will also increase the temperature difference between cold and warm in the tropical stratosphere. The greater the temperature difference, the stronger the wind, which in turn makes the atmospheric circulation in the troposphere more active, ultimately affecting global weather patterns. This research provides the first systematic lidar-based dataset on low-latitude mesopause fluxes, offering valuable insights for aerospace engineering, satellite orbit prediction, and atmospheric modeling. For instance, precise temperature and wind profiles improve the safety of spacecraft reentries and high-altitude flights by accounting for upper atmospheric variability. For more details, access the full observational dataset via the Science Data Bank or explore the SABER satellite’s public data repository. Stay tuned for future articles diving deeper into the lidar’s technical innovations, observation site selection, and advanced data processing methods! The mysteries of the sky extend far beyond what meets the eye. As this Hainan-based lidar continues to monitor the mesopause, it promises to unlock more secrets of Earth’s upper atmosphere—contributing vital Chinese data and solutions to global atmospheric science.

Recent highlights in Biogeosciences

nicola — Tue, 24 Mar 2026 09:26:31 +0000

Want to know more about the latest breakthroughs in biogeochemistry?

Then you’ve come to the right place. Across marine biogeochemistry, fisheries science, and environmental health, new research is mapping the unintended consequences of a warming and increasingly exploited planet. By tracing carbon and contaminants through water, sediments, and food systems, these studies offer a portrait of Earth’s shifting balance.

Below, we highlight three of the most recent publications from Biogeosciences.

Carbon on the move: What a global model reveals about dissolved organic carbon in a warming ocean

[caption id="attachment_3819" align="alignleft" width="1024"] Fig. 1: DOC export rates at 100 and 1000 m and projected changes. Present-day (a, c); future minus present (b, d). Negative values indicate upward transport. Dots mark regions with significant changes (α=0.05) (Flanjak et al., 2025).[/caption]

The ocean stores about ten times more carbon than land and atmosphere combined, largely by transporting carbon from the surface to long term deposits on the seafloor, helping regulate Earth’s climate. Biological processes in the sunlit surface ocean initiate this storage: microalgae (phytoplankton) use light to fix CO₂ into organic matter , which then enters the marine food web. Organic carbon then takes one of two pathways to long-term storage: as particulate organic carbon (> 0.45 µm), which sinks as marine snow and fecal pellets, and as dissolved organic carbon (DOC), a soup of small molecules released through exudation, grazing, and viral lysis. POC sinks directly onto the ocean floor and has long been recognized as a major export route to the deep ocean, whereas DOC is a major food source for bacteria and fuels the microbial loop in the surface layer while being transported by currents rather than gravity.

But climate change is reshaping this system. This study analyzes the changes happening in DOC export under the projected ‘worst-case’ high-emission scenario through biogeochemical modelling. As surface waters continue to warm, stratification strengthens, reducing vertical mixing and the upward supply of nutrients that support primary production. Biological productivity declines, reducing DOC production. Yet paradoxically, DOC concentrations in the upper ocean increase, since physical transport of DOC below 100 meters is slowed down. With less DOC is produced, even less is exported. Most of what does leave the surface is consumed by bacteria before reaching the deep sea, with deep flux far smaller than at shallow depths. Overall, the projected decline in DOC export amounts to 6%, confirming the expected downward trend.

Therefore, the ocean’s carbon story is not just about sinking particles but also about invisible pathways of dissolved carbon species shaped by physics. Globally, DOC accounts for about one-fifth of organic carbon export at 100 meters, and far more in nutrient-poor subtropical gyres, highlighting how understanding biological and physical processes shaping DOC cycling will be beneficial to better understand the role of DOC in the marine carbon cycle under ongoing climate change.

Read the full article here: Flanjak et al., 2025, Dissolved organic carbon dynamics in a changing ocean: an ESM2M-COBALTv2 coupled model analysis, Biogeosciences, 22, 6877–6894

Impact of mobile bottom fishing on organic carbon in seabed sediments – why we focussed on currently unimpacted areas

[caption id="attachment_3821" align="alignright" width="1024"] Fig. 2: Vulnerable organic carbon stocks of the surface layer for the three fishing impact scenarios: (a) low, (b) mean and (c) high. Existing area-based protection measures Area-based protection measures based on the regulation on the protection of coral reefs, Paragraph 58 of the harvest regulations, and the regulation on vulnerable marine ecosystems (VMEs). Rock refers to hard substrates, mainly rock and boulders. Source of land areas: ESRI (Diesing et al., 2025).[/caption]

Continental margins are global hotspots of long-term organic carbon burial, quietly locking away a fraction of the carbon fixed by phytoplankton each year and playing a crucial role in climate regulation. Of the roughly 50 gigatons of carbon fixed annually, only a tiny share ultimately reaches the seafloor—and just about 10% of that is buried for the long term, indicating how this process takes place over long time-scales . Along the Norwegian continental margin, large stocks of organic carbon remain stored in surface sediments, especially in those undisturbed by mobile bottom fishing. Norway has already implemented extensive spatial protections, including coral reef protections, a long-standing closure west of Svalbard, and expanded safeguards in the Barents Sea, creating a unique opportunity to examine what is still intact.

Mobile bottom fishing, which drags weighted nets across the seabed, can resuspend sediments and stimulate microbial remineralisation, potentially converting stored organic carbon back into CO₂. Estimates of trawling-induced CO₂ release vary widely, yet surface sediments are consistently identified as especially vulnerable. By combining vessel monitoring data (2009–2020), spatial sediment modeling, and a meta-analysis of experimental studies, we estimated how much carbon in currently unfished areas could be at risk if trawling expands. We find that 207 million metric tons of organic carbon are stored in surface sediments, 139 million of which lie in unfished areas. Of these, about 19 million metric tons, primarily in the Barents Sea, could be vulnerable to disturbance, with uncertainty bounds ranging from 2 to 34 million metric tons.

Large amounts of organic carbon remain stored in seafloor areas of the Norwegian continental margin that have not yet been disturbed by mobile bottom fishing—and these untouched stores are among the most vulnerable to future impacts. By identifying where this vulnerable carbon is located and how much could be lost if trawling expands into these areas, this study provides a practical evidence base for management. Protecting unfished, carbon-rich seabed areas now is one of the most effective ways to prevent avoidable carbon loss and to maintain the ocean’s role in climate regulation.

Read the full publication here: Diesing et al., 2025,Mapping organic carbon vulnerable to mobile bottom fishing in currently unfished areas of the Norwegian continental margin, Biogeosciences, 22, 7611–7624

Review of Artisanal Small-scale Gold Mining (ASGM) derived mercury in agricultural systems: an unhealthy competition for space

Artisanal and small-scale gold mining (ASGM) may sound almost folksy, conjuring up images of miners panning for gold beside mountain streams. However, next to providing livelihoods for an estimated 20 million people while supplying up to one-third of the world’s gold, it is the world’s largest anthropogenic source of mercury. Booming gold prices have driven its rapid expansion across Africa, Asia, and Central and South America, where mercury amalgamation remains the dominant extraction method because it is cheap and effective. Yet this process releases vast amounts of mercury into air, soils, and waterways.

This study synthesises current research on the pervasive contamination of agricultural systems by ASGM-derived mercury, identifying the key environmental pathways and subsequent risks to food security.

It becomes clear that the consequences of mercury amalgamation extend far beyond polluted rivers and mining sites. Once emitted, mercury can redeposit locally or travel long distances, entering agricultural systems through atmospheric uptake by leaves or deposition to soils. Crops grown near ASGM sites—including cassava, soy, pumpkin, peanuts, maize, sweet potato, and other crops—have been found to contain dangerously high levels of inorganic mercury, sometimes exceeding safe daily intake thresholds. Mercury is absorbed into plant tissues via two main pathways: through the atmosphere, especially in leaves, and from roots of saturated soil crops. Rice poses a particular concern: cultivated in flooded paddies that favor mercury methylation, it can accumulate both total mercury and methylmercury, with many samples surpassing safety guidelines. Animal products such as eggs, meat, and milk may also carry elevated mercury levels, though this pathway remains understudied.

Therefore, ASGM represents not only a mining or environmental issue but one of potential food security and public health. Addressing it requires better monitoring of soil–plant–atmosphere pathways, deeper investigation into mercury in crops and livestock, and stronger collaboration between international researchers and local communities to translate science into protective action, so that academic research can better support the existing local efforts to advance public health through education, changes in practice, and advocacy.

Read the full publication here: McLagan et al., 2025, Reviews and syntheses: Artisanal and small-scale gold mining (ASGM)-derived mercury contamination in agricultural systems: what we know and what we need to know, Biogeosciences, 22, 6695–6726

Edited by Nicola Krake

When European pollution reshaped the Asian summer monsoon

Shalenys Bedoya — Mon, 23 Mar 2026 07:30:09 +0000

[caption]

Figure 1. JJA precipitation changes across Asia in mm d^-1 (55 yr)^-1 for 1901-1955. Map (a) displays observed rainfall patterns, while (b) isolates the specific influence of European aerosols on these trends. (c) tracks rainfall anomalies in central-northern India from 1901 to 2000, comparing real-world observations (black/red) against climate model simulations (colors). Data is smoothed over 11-year periods to highlight long-term fluctuations, with dashed lines showing the overall trajectory and grey shading representing model uncertainty. This early-century intensification of the monsoon has received far less attention than the late-twentieth-century weakening. Yet understanding it is crucial. If we want to predict how the monsoon will respond to future pollution reductions and greenhouse gas emissions, we must understand how it responded in the past.[/caption]

The Asian summer monsoon is one of the most powerful climate phenomena on Earth. Each year, it brings life-giving rainfall to billions of people across South and East Asia. Its arrival determines harvests, water supply, food security, and economic stability. We often think of the monsoon as something driven locally: by the heating of the Indian subcontinent, by ocean temperatures, or by regional pollution. But what if part of its history was shaped thousands of kilometres away? In our recent study (published in Atmospheric Chemistry and Physics, ACP), we show that air pollution from Europe helped shaping the Asian summer monsoon in the early twentieth century.

An overlooked shift in Asian rainfall

Rain gauge records reveal a striking pattern in the first half of the twentieth century. From about 1900 to the mid-1950s rainfall increased over central and northern India concurrent with a southward shift over China, creating wetter conditions in the south and drier conditions along the Yangtze River valley (Figure 1). These changes later reversed in the second half of the century. This early-century intensification of the monsoon has received far less attention than the late-twentieth-century weakening. Yet understanding it is crucial. If we want to predict how the monsoon will respond to future pollution reductions and greenhouse gas emissions, we must understand how it responded in the past. At the start of the twentieth century, industrial emissions in Asia were still relatively small. In contrast, Europe had already undergone decades of industrialisation. Coal burning released large amounts of sulphur dioxide, which forms sulphate particles in the atmosphere. These tiny particles reflect sunlight and brighten clouds, cooling the surface below.

Could European pollution have influenced rainfall in Asia?

Testing the idea with a climate model

To answer this question, we used a state-of-the-art global climate model. We ran two sets of historical simulations covering 1850 to 2005: a simulation including all known historical influences, such as greenhouse gases and aerosols, and an identical simulation, except that European sulphur emissions were fixed at pre-industrial levels. By comparing the two, we could isolate the effect of European sulphate pollution. The result was striking. When European sulphate emissions were allowed to increase, the model produced more rainfall over central and northern India, and a southward shift in rainfall over East Asia. These patterns closely resemble what is seen in historical observations (Figure 1). A clear pattern of large-scale circulation changes linking Europe to Asia was also evident. In other words, European pollution was not just a regional phenomenon. It helped shape the behaviour of the Asian summer monsoon.

How can pollution in Europe affect rainfall in India and China?

The key lies in atmospheric circulation.

Sulphate particles over Europe reduced incoming sunlight and cooled the surface. The atmosphere responded by forming a region of higher pressure over central and eastern Europe. This surface change extended upward into the upper troposphere. That upper-level disturbance did not stay local. It triggered a large-scale wave pattern in the atmosphere known as a Rossby wave. These waves are planetary-scale meanders that can transmit disturbances across continents. In our simulations, the wave pattern propagated eastward from Europe across the Middle East into South Asia, and onward to East Asia and the Pacific. As the wave travelled, it altered wind patterns at low levels over Asia. These wind changes redirected moisture transport. Moist air was steered toward central and northern India, increasing rainfall, while circulation shifts over East Asia reorganised rainfall bands, producing the observed north-south contrasts. The monsoon changes were therefore not simply a matter of temperature differences between land and ocean. Instead, they were driven by a dynamical pathway linking European cooling, atmospheric wave response, altered Asian circulation, and redistributed rainfall (Figure 2). [caption id="attachment_5438" align="alignnone" width="561"] Figure 2. Spatial patterns of the 1901–1955 linear trends of the JJA average (a) 300 hPa wave activity flux (vectors; 10⁻⁴ m² s⁻²(55 yr)⁻¹) and streamfunction (shades; 10⁵ m² s⁻¹ (55 yr)⁻¹), and (b) 300 hPa meridional wind (contours; m s⁻¹ (55 yr)⁻¹) and 500 hPa vertical velocity (shades; 10⁻² Pa s⁻¹ (55 yr)⁻¹) associated with increased European sulphate aerosols.[/caption]

Why this matters today?

Sulphur emissions in Europe have declined sharply since the late twentieth century due to air quality regulations. At the same time, emissions in parts of Asia rose and are now also decreasing in many regions. Our findings highlight an important lesson: air pollution does not respect national boundaries. Its climate effects can be remote and unexpected. If European sulphate pollution once strengthened the South Asian monsoon, then its reduction may contribute to weakening it — potentially offsetting or interacting with the effects of Asian pollution changes and greenhouse gases. Future monsoon behaviour will depend on a complex mix of greenhouse gas warming, regional aerosol reductions, remote aerosol changes, and internal climate variability. Understanding these interacting influences requires looking beyond local forcing and considering the global atmospheric connections that tie continents together.

Looking back to see forward

The early twentieth century provides a natural experiment. Asian emissions were still modest, while European emissions were already substantial. This separation helps us identify cause and effect more clearly than in recent decades, when emissions have been widespread. By revisiting this overlooked period, we gain insight into how regional pollution can trigger large-scale atmospheric adjustments. These dynamical pathways may also operate in the future as emission patterns continue to evolve. The Asian summer monsoon supports more than half of the world’s population. Understanding its sensitivity to both local and remote human activities is therefore not only a scientific challenge, but a societal priority. The story of European sulphate pollution and the Asian monsoon reminds us that Earth’s climate system is deeply interconnected. Actions in one region can reverberate across the planet — sometimes in ways we are only now beginning to understand.

Takeaway message

1. Air pollution in Europe influenced Asian rainfall patterns in the early twentieth century.
2. The connection occurred through large-scale atmospheric waves linking Europe and Asia.
3. This highlights how regional emissions can have global climate impacts.

This post has been edited by the editorial board.

References 

Sun, W., Bollasina, M. A., Colfescu, I., Wu, G., and Liu, Y.: European sulphate aerosols were a key driver of the early twentieth-century intensification of the Asian summer monsoon, Atmos. Chem. Phys., 26, 2027–2039, https://doi.org/10.5194/acp-26-2027-2026, 2026.

Geomythology and Science: a long lasting yet hidden relationship

Filippo Carboni — Thu, 19 Mar 2026 11:00:43 +0000

The links between geomythology and science are considerable and officially began with the works of Vitaliano (EGU Blog – Geomythology. True science and/or strong communication medium ?!) and continues nowadays thanks to the Geoheritage Journal edited by Springer Nature, and evident in two proposed sessions to the EGU sessions, including one from the 2025 conference entitled “Geomythology: Bridging the Humanities and Geosciences” and a 2026 panel, “Mythogenic Landscapes”. In addition, the ScienceDirect database currently lists nearly 40 papers with “geomythology” in the title and many more related to the topic; a Google Scholar research shows about 1360 publications with “Geomythology” in the title and/or as a content.

Proceeding Vitaliano

Yet Vitaliano had important predecessors, including Euhemerus, a 4^th century BC philosopher, one of the first to analyse the Greek gods from a rationalistic perspective. He had an epiphany of sorts when he encountered a stele on what is now the island of Socotra (Yemen), listing the birth and death years of members of the Greek pantheon. Euhermerus came to regard those figures, not as supernatural, but as local, human leaders who had been promoted to divine status through legends. His approach, known as euhemerism, influenced Vitaliano’s definition of geomythology as “the geologic application of euhemerism”. Other precursors include Palaephatus, Euehemerus’s protégé, who composed a work of paradoxography entitled On Incredible Things, in which he examines mythical persons from a naturalistic perspective. For instance, the Amazons, he contends, were not warrior women, but men who wore long skirts and ribbons in their hair, yet who were also able to fight (On Incredible Things, section 32). Palaephatus also dismissed the idea of men flying, suggesting instead that Daedalus and Icarus were imprisoned by King Minos, until Daedalus escaped and lowered Icarus through the prison window in a basket. They then sailed away, pursued by Minos’s men, and when a strong wind caught their boat, it was as if they were “flying” (Fig.1). However, the boat also capsized, and while Daedalus was able to swim to shore, Icarus drowned (On Incredible Things, section 12). [caption id="attachment_13020" align="alignleft" width="279"] Fig. 1. The Fall of Icarus. Jacob Peter Gowy (1635 – 1637). Museo Nacional del Prado, Madrid, D.C. Public Domain.[/caption] Palaephatus’s work can make for tedious reading, yet some of his explanations are plausible, such as his account of the founding of the Greek city of Thebes. According to this legend, on his way to rescue his sister Europa, who had been abducted by Zeus, the Phoenician prince Cadmus slew a dragon, then sowed the dragon’s teeth in the ground; the teeth yielded a crop of fierce warriors who helped him start the city (Fig. 2). Yet Palaephatus argues that the teeth were those of an elephant (Greek eléphās) and were initially owned by King Drakon of Thebes (On Incredible Things, section 3). Cadmus came to this region of Greece, after falling out with brother/rival Phoenix, then killed Drakon and seized the crown. At this point, Drakon’s friends fought back, and when Cadmus bested them, they fled, taking with them Drakon’s treasures, including the teeth. Eventually, men from other regions rose up against Cadmus, and the Theban citizens concluded that Cadmus’s king-slaying was an evil action, and that Drakon’s teeth had created this new crop of warriors. [caption id="attachment_12981" align="alignleft" width="300"] Fig. 2. Cadmus Fighting the Dragon. Hendrik Goltzius. Statens Museum for Kunst, 1500. Public Domain.[/caption] This “explanation” may be convoluted, true, yet it constitutes one of the first instances of an ancient thinker recognizing the truth informing a legendary claim, namely, that the so-called dragon teeth were in fact molars from an ancient species of pachyderm. Hence, we might put Palaephatus among the first geomythologists. More recent figures who anticipated Vitaliano’s insights are Robert Hooke (1635–1703), the “English Leonardo” who grappled with the riddle of how fossilized marine organisms are found at the top of high mountains, far from the ocean. Hooke conjectured that some mountains were once lower lands that had been raised up by earthquakes. In his Lectures and Discourses of Earthquakes and Subterranean Eruptions (1667–68), he explains this claim mythologically, by alluding to the Gigantomachy, the legendary war of the Giants (including figures such as Enceladus, Mimus, and Polybotes) against the Olympians. Hooke argues that the poets Ovid and Virgil told this narrative as a way of explaining the actions of earthquakes and volcanoes. In Ovid’s account, for instance, the Giants pile up rocks and stones to bring themselves close to heaven. From there, they threaten the Olympians, but are overthrown by Zeus’s thunderbolts, then imprisoned under the earth (Metamorphosis, 1.183 et passim) (Fig. 3). [caption id="attachment_12984" align="alignleft" width="300"] Fig. 3. Enceladus. Gaspar Mercy. Gilt-bronze. Versailles, France. Photo by Coyau. Uploaded 6 May 2011.[/caption] Ovid specifically names Mt. Olympus, Mt. Ossa, and Mt. Pelion as the locations of the battle; it is interesting to note how these locations all fall in the Thessaly region, which is characterized by active and seismogenic normal faults and was hit by a few earthquake induced tsunamis (Kassaras et al., 2020, Fig. 4). Another scientist who presaged Vitaliano is Georges Cuvier (1769-1832), the father of palaeontology. He kept careful records of all fossil and bone finds in America, as well as legends told about them. As a result, among other things, he was able to refute Thomas Jefferson’s hypothesis that the Incognitum, an allegedly carnivorous elephant, still roamed the western half of the United States. In fact, Cuvier posited that these animals were now extinct, and, further, that they were herbivorous; he turned out to be correct. [caption id="attachment_12993" align="alignleft" width="1600"] Fig. 4. Structural map showing the topography, bathymetry, seismogenic faults and earthquake related tsunamis of the Thessaly area and surroundings (Modified after Kassaras et al., 2020).[/caption] Cuvier, along with Virgil, Ovid, and Hooke, as well as figures like them, matter because they show that geomythology is not a recent fad, but rather, an idea with significant pre-modern roots.

References

Hooke, R., 1667–1668. Lectures and Discourses of Earthquakes and Subterranean Eruptions. Kassaras, I., Kapetanidis, V., Ganas, A., Tzanis, A., Kosma, C., Karakonstantis, A., Valkaniotis, S., Chailas, S., Kouskouna, V., Papadimitriou, P., 2020. The New Seismotectonic Atlas of Greece (v1.0) and Its Implementation. Geosciences 10(11), 447. https://doi.org/10.3390/geosciences10110447. Ovid, Metamorphoses. Translated By Samuel Garth, John Dryden, et al. The Internet Classics Archive, http://classics.mit.edu/Ovid/metam.html. Consulted on 09.03.2026. Palaephatus, On Incredible Things. Translated by John Brady Kiesling. Consulted on 09.03.2026.

Improve your chances in hiring processes and proposal evaluations: curate your ORCID

Bettina Schaefli — Thu, 19 Mar 2026 09:30:15 +0000

Today – while preparing my latest Sience - CV (SciCV) version for a proposal submission - I noticed that I will soon celebrate my 20th net-academic-age birthday* (see below). No worries, my editorial is not about looking back on my career, but about offering some hints on how to keep up with evolving research evaluation practices. One of the things that is evolving quickly (for academic standards!) is the analysis of publication lists and of research output: for many job applications or proposal submissions, you are no longer asked to produce a full list of publications but to provide a selection of your most important works. This is to follow modern research assessment standards as e.g. defined by the DORA declaration or the Coalition for Advancing Research Assessment, COARA: with a focus on quality and diversity of scientific outputs rather than on quantity and journal-based metrics.

The role of ORCID in research evaluation

Some selection or evaluation committees go a step further and do not formally allow their members to consult web-based publication lists of candidates other than the data provided by ORCID. The rationale for this is to evaluate only the material that the candidates provide themselves – ORCID being an acceptable extension since your ORCID entry is under your control. And ORCID does not contain unwanted metrics such as impact factors. However, ORCID needs to be curated to facilitate the work of people who evaluate your academic profile. You can add a short bio (free text) and links to your websites or to other scientific databases. The core part of your ORCID-entry is the employment & education history, your scientific output (“works”, see figure below), acquired funding and professional activities (e.g. memberships, service work), including peer-review. [caption id="attachment_13596" align="aligncenter" width="700"] View of the ORCID entry with database categories[/caption] These categories cover the type of information that is needed to assess your academic profile and all of them should be populated with information that gives a complete picture of your activities and achievements. You can also (temporarily) sharpen your profile by selecting which entries are publicly visible and which entries you deem less important (hidden or deleted) for your current profile.

Show the diversity of your output

Most importantly, you need to manually add “works” other than journal papers and conference abstracts (imported automatically) to demonstrate the diversity of your work. This includes datasets, codes and preprints but also outreach or teaching activities (see figure below). [caption id="attachment_13597" align="aligncenter" width="700"] Options to manually add works to your ORCID entry[/caption] You can also highlight your 5 most important works. Do not forget to check all automatically added / imported items and replace those that are confusing: for example, if you have abstracts from EGU conferences (published on egusphere), they appear automatically labelled as “preprints”. If you have many of those, a potential reviewer might think that you produce more preprints than actual papers. To avoid this, you can delete an imported entry and replace it with a manual entry that is labelled “conference paper” (attention: you cannot edit imported entries, only replace them). Another typical problem: some imported entries do not show the contributors – annoying for someone who wants to see your first author papers. Again, the solution is to replace it with a manually added entry.

Contribute to change

If much of the above is new for you: discuss these new research evaluation standards with your peers, within your university, research institute or evaluation committee. If we want to make a change, we need a collective effort. I am a member of different committees that do not yet fully adopt these modern evaluation standards. This implies regular discussions on how to focus on the quality of the work rather than on the number of papers or on the name of the journal. And do not forget to check if your university or your national funding agency signed the DORA declaration or is a member of COARA - this might be a strong argument for your colleagues to evolve towards these new standards. * Academic age: the time someone spent doing research in academia or public research institutions after completing their PhD. Usually, the net academic age is used in profile evaluation or for eligibility windows for career grants such as ERC starting grants. The net academic age is the academic age minus any time period with a justified interruption such as for care duties, illness, non-scientific work etc. See e.g. the official definition of the Swiss National Science Foundation, SNFS, pdf.).

Subduction interfaces are complicated - and that’s their beauty!

Editorial Team 4 — Wed, 18 Mar 2026 09:00:40 +0000

The dynamics of subduction zones are strongly influenced by the subduction interface. Understanding its rheology enables geodynamic modellers to better simulate these systems and unravel the fundamental processes that govern them. In today’s blog post, we explore subduction interface rheology and discuss effective approaches for modelling it. [caption id="attachment_42448" align="alignleft" width="225"] I am a geophysicist-turned-geodynamicist currently working as an Assis-
tant Professor at the School of Geosciences at the University of Louisiana
at Lafayette (yes, we DO have alligators on campus). I approach geodynam-
ics from a rheological perspective and have mostly focused my research on
subduction interface deformation. My rheology skills are highly transferable,
mainly in baking[/caption]

What is a subduction interface?

I first met a subduction interface in person in August of 2015, during my first year as a PhD student at GFZ Potsdam, under the supervision of Prof. Onno Oncken. Herr Oncken led a field trip to the Central Alps, tracing the paleo-interface (Bachmann et al., 2009a,b) during the subduction of the Penninic ocean underneath the continental realm of the Adriatic plate (Austroalpine nappes; Froitzheim et al., 1996). The exposed plate interface has experienced frictional and viscous deformation over an extended period of time, reflecting a multistage evolution (Bachmann et al., 2009a). But first things first! Subduction zones are the largest physical and chemical systems within the Earth, responsible for recycling large amounts of rocks and fluids from the Earth's surface to its interior and vice versa (e.g., Stern, 2002; Hacker et al, 2003a,b). As the downgoing slab subducts beneath the overriding plate, some portions of the finite thin zone connecting the two plates slide freely past each other. In contrast, others remain mechanically locked due to coupling, resulting in the accumulation of stresses and storage of elastic deformation within and adjacent to their place of contact (interface - aha!). After a certain threshold value of stress is reached, stored elastic energy is released by sudden slip, and thus, decoupling of the interface occurs at a typical depth range between 5 and 45 km, generating interplate earthquakes. Much of the deformation processes that take place during convergence and subsequent subduction are accommodated by deformation along the interface of the involved plates (Hacker et al., 2003a; Agard et al., 2018). Due to the mechanical coupling of the plates, it is possible that stresses are periodically built up and suddenly released in the form of earthquakes. Important factors that affect the coupling of the interface are the lithology and lubrication of the interface, its rheology, and how these vary with depth. In order to assess these properties in active subduction interfaces, one must look into the rock record of exhumed subduction interfaces (Grigull et al., 2012; Wassmann and Stockhert, 2013b; Agard et al., 2018). The plate interface is intrinsically weak, with low (< 35 MPa) shear stresses acting upon it (e.g., Duarte et al., 2015). A paradox therefore emerges: how can these weak zones store elastic stresses high enough to eventually produce some of the most catastrophic earthquakes ever recorded on the planet? *cue heterogeneity* Some minerals/rocks are weaker than others and thus can withstand low stresses before yielding (for example, quartz starts flowing at ∼ 350ºC, while feldspar at the same temperature is solid as a rock - pun intended). A useful parameter for describing the rheology of the subduction interface is the effective viscosity, η, which, by definition, is sensitive to changes in the strain rate, ε (η = τ / 2ε), where τ is the second invariant of the deviatoric stress tensor). As such, the effective viscosity of the interface strongly depends on the dominant/faster mechanism accommodating deformation (Stockhert, 2002; Wassmann and Stockhert, 2013b). A diagram commonly used to represent the strength of the lithosphere is given in Figure 1. [caption id="attachment_42444" align="aligncenter" width="1270"] Figure 1: Models of strength through continental lithosphere (also known as
Christmas tree diagrams). In the upper crust, frictional strength increases
with pressure and depth. From Burgmann and Dresen, 2008.[/caption] Dissolution-precipitation creep tends to dominate at the shallower parts of the subduction interface, while dislocation creep takes over at higher depths. Concurrently, locally frictional processes and high pore fluid pressures are deduced by the presence of sealed cracks. Frictional and viscous shearing are competing mechanisms responsible for coupling and de-coupling of the interface. From ample field observations, it is evident that the subduction interface is far from homogeneous (e.g., Vannucchi et al., 2008; Fagereng and Sibson, 2010; Grigull et al., 2012, Angiboust et al., 2015; Behr, et al., 2018; Kotowski and Behr, 2019). This heterogeneity implies deformation within the interface at different strain rates and, therefore, some of its components might show frictional behaviour, while others may deform viscously. Although the previously mentioned flow laws account for one type of deformation mechanism being active at a time, more than one mechanisms can be active simultaneously in a rock. The rheology of an aggregate is, therefore, dependent on the collective deformation of the constituent minerals (Handy, 1990; Platt, 2015). [caption id="attachment_42445" align="aligncenter" width="1600"] Figure 2: A: Eclogite boudin showing dilational veins at both high and low
angles to the foliation. B: Thrust-sense dilational shear fracture filled with
quartz offsetting an omphacite-rich band and merging into viscous shear in
surrounding blueschist. From Behr et al., 2018.[/caption]

How do we model such complexity (and beauty)?

It's all about the rheology! To describe the relation between the stress exerted on a material and the strain rate at which it deforms, flow laws of the following form have been invoked from experimental studies: where ε is the strain rate, A a material constant, σ the stress, n the stress exponent, d the grain size in μm, m the grain size exponent, f is the water fugacity (this term has been explained to me about a million times, and I swear I still have no idea what it really is), r the fugacity exponent (see previous desperate parenthetical comment), Q the activation energy, p the applied pressure, V the activation volume, R the molar gas constant, and T the absolute temperature. Flow law parameters are determined from deformation experiments under known conditions (pressure, temperature, strain rate, or stress); then, the microstructures are studied in order to assess which deformation mechanism controls the strain rate. The most commonly studied deformation mechanism that has been reproduced experimentally and is predominantly used in geodynamics models is dislocation creep. However, most field observations in active subduction shear zones point to pervasive pressure-solution creep. Now it is time to make some executive decisions; otherwise it is very easy to go down the rabbit hole of infinite (oh, the drama!) subduction interface complexity. But don't panic - pick the processes that are most relevant for your research and focus on them. I always find it useful to make a few Christmas tree diagrams with various flow laws that could describe my geological setting. Are there field observations in your area? If yes, what is the mechanism that accommodates most of the deformation, and at what depth do you see the frictional to viscous transition? If no field observations are available, are there exhumed rocks that are equivalent to your research in other parts of the world? Look at the rock record for inspiration! ...to be continued...

References:

Agard, P., Plunder, A., Angiboust, S., Bonnet, G., & Ruh, J. (2018). The subduction plate interface: Rock record and mechanical coupling (from long to short timescales). Lithos, 320–321, 537–566. https://doi.org/10.1016/j.lithos.2018.09.029

Angiboust, S., Kirsch, J., Oncken, O., Glodny, J., Monié, P., & Rybacki, E. (2015). Probing the transition between seismically coupled and decoupled segments along an ancient subduction interface. Geochemistry, Geophysics, Geosystems, 16(6), 1905–1922. https://doi.org/10.1002/2015GC005776

Bachmann, R., Glodny, J., Oncken, O., & Seifert, W. (2009). Abandonment of the South Penninic-Austroalpine palaeosubduction zone, Central Alps, and shift from subduction erosion to accretion: Constraints from Rb/Sr geochronology. Journal of the Geological Society, London, 166(2), 217–231. https://doi.org/10.1144/0016-76492008-024

Bachmann, R., Oncken, O., Glodny, J., Seifert, W., Georgieva, V., & Sudo, M. (2009). Exposed plate interface in the European Alps reveals fabric styles and gradients related to an ancient seismogenic coupling zone. Journal of Geophysical Research: Solid Earth, 114(5), 1–23. https://doi.org/10.1029/2008JB005927

Behr WM, Bürgmann R. 2021. What’s down there? The structures, materials and environment of deep-seated slow slip and tremor. Phil. Trans. R. Soc. A 379: 20200218. https://doi.org/10.1098/rsta.2020.0218

Behr, W. M., Kotowski, A. J., & Ashley, K. T. (2018). Dehydration-induced rheological heterogeneity and the deep tremor source in warm subduction zones. Geology, 46(5), 475–478. https://doi.org/10.1130/G40105.1

Burgmann, R., & Dresen, G. (2008). Rheology of the Lower Crust and Upper Mantle: Evidence from Rock Mechanics, Geodesy, and Field Observations. Annual Review of Earth and Planetary Sciences, 36(1), 531–567. https://doi.org/10.1146/annurev.earth.36.031207.124326

Duarte, J. C., Schellart, W. P., & Cruden, A. R. (2015). How weak is the subduction zone interface? Geophysical Research Letters, 42(8), 2664–2673. https://doi.org/10.1002/2014GL062876

Fagereng, Å., & Sibson, R. H. (2010). Mélange rheology and seismic style. Geology, 38(8), 751–754. https://doi.org/10.1130/G30868.1

Froitzheim, N., & Manatschal, G. (1996). Kinematics of Jurassic rifting, mantle exhumation, and passive-margin formation in the Austroalpine and Penninic nappes (eastern Switzerland). Geological Society of America Bulletin, 108(9), 1120–1133. https://doi.org/10.1130/0016-7606(1996)108\%253C1120:KOJRME\%253E2.3.CO;2

Grigull, S., Krohe, A., Moos, C., Wassmann, S., & Stockhert, B. (2012). “Order from chaos”: A field-based estimate on bulk rheology of tectonic mélanges formed in subduction zones. Tectonophysics, 568–569, 86–101. https://doi.org/10.1016/j.tecto.2011.11.004

Hacker, B. R., Abers, G. A., & Peacock, S. M. (2003). Subduction factory 1. Theoretical mineralogy, densities, seismic wave speeds, and H 2 O contents. Journal of Geophysical Research: Solid Earth, 108(B1), 1–26. https://doi.org/10.1029/2001jb001127

Hacker, B. R., Peacock, S. M., Abers, G. A., & Holloway, S. D. (2003). Subduction factory 2. Are intermediate-depth earthquakes in subducting slabs linked to metamorphic dehydration reactions? Journal of Geophysical Research: Solid Earth, 108(B1). https://doi.org/10.1029/2001jb001129

Handy, M. R. (1990). The Solid-State Flow of Polymineralic Rocks. Journal of Geophysical Research, 95(B6), 8647–8661.

Kotowski, A. J., & Behr, W. M. (2019). Length scales and types of heterogeneities along the deep subduction interface: Insights from exhumed rocks on Syros Island, Greece. Geosphere, 15(4), 1038–1065. https://doi.org/10.1130/GES02037.1

Platt, J. P. (2015). Rheology of two-phase systems: A microphysical and observational approach. Journal of Structural Geology, 77, 213–227. https://doi.org/10.1016/j.jsg.2015.05.003

Stern, R. J. (2002). Subduction zones. Reviews of Geophysics, 40(4), 1395–1406. https://doi.org/10.1029/2001RG000108

Vannucchi, P., Remitti, F., & Bettelli, G. (2008). Geological record of fluid flow and seismogenesis along an erosive subducting plate boundary. Nature, 451(7179), 699–703. https://doi.org/10.1038/nature06486

Wassmann, S., & Stockhert, B. (2012). Matrix deformation mechanisms in HP-LT tectonic mélanges—Microstructural record of jadeite blueschist from the Franciscan Complex, California. Tectonophysics, 568–569, 135–153. https://doi.org/10.1016/j.tecto.2012.01.009

Why did the Amazon forest become a CO2 source in 2023?

Bikem Ekberzade — Tue, 17 Mar 2026 16:51:15 +0000

When simulations help highlight an anomaly, scientists who are curious commit to dig deeper, and of course when resources but most importantly data is available, you get good science. In the third episode of the EGU Biogeosciences Division podcast series Bikem Ekberzade talks with Santiago Botia to look at the story behind a recent study that was published in AGU Advances. You can listen to the podcast here:

Reduced Vegetation Uptake During the Extreme 2023 Drought Turns the Amazon into a Weak Carbon Source

Photo credit: Chennawit U, Pexels

From Seismic Signals to Safer Trains: Italy’s First Earthquake Early Warning System for High-Speed Railways

hediehsoltanpour — Mon, 16 Mar 2026 16:38:16 +0000

Earthquakes remain among the most disruptive natural hazards worldwide, capable of causing sudden loss of life, severe economic damage, and long-lasting societal impacts. One of the most effective tools developed in recent decades to mitigate these effects is Earthquake Early Warning (EEW), a real-time monitoring strategy that exploits a fundamental physical property of earthquakes: seismic waves do not propagate instantaneously, and their speed is much slower than the light-speed at which the information travel through communication channels. When an earthquake initiates, the first, low-amplitude signals to radiate are primary, or P waves, which travel rapidly through the Earth but generally cause little damage. They are followed by slower secondary (S) and surface waves, which carry most of the destructive energy. EEW systems are designed to detect the first, weak signals and to rapidly analyse their characteristics to forecast the expected ground shaking before it affects vulnerable targets [1, 2] (Figure 1). Even a few seconds of advance notice can be crucial, allowing automated or human responses that reduce risk, such as stopping trains, slowing industrial processes, or warning people to take self-protective actions (Figure 2). [caption id="attachment_10785" align="aligncenter" width="357"] Figure 1. EEWS principles. a) P-waves are quickly detected from one or more sensors and used to estimate the potential impact of ground shaking at target sites. b) Real-time estimates are used to alert sites before the arrival of the most damaging waves. (Image credit: Authors; produced by SciAni. Screenshots from the video “Earthquake early warning: how to and what for?)[/caption] [caption id="attachment_10811" align="aligncenter" width="489"] Figure 2. Example of different real-life situations that could benefit from EEW alerts: from the protection of children in schools, to the activation of automatic emergency actions. (Image credit: Authors; produced by SciAni. Screenshots from the video “Earthquake early warning: how to and what for?)[/caption] Over the last twenty years, earthquake early warning has transitioned from a scientific concept to an operational reality in several earthquake-prone regions, including Japan, Mexico, Taiwan, China, and parts of the United States, while Europe has increasingly explored its feasibility and potential benefits [3, 4, 5, 6]. This post explores how a new, end-to-end EEW system is being used to protect Italy’s high-speed rail network, transforming seconds of seismic data into automated safety actions.

Why High-Speed Trains Need Early Warning

Railway infrastructures represent one of the most challenging and strategic applications of earthquake early warning, especially for high-speed trains travelling at hundred kilometres per hour, and relying on sophisticated safety control systems. Earthquakes can threaten railways in multiple ways: they may damage tracks, bridges, tunnels, and embankments, or produce sudden ground deformations that compromise track geometry. Even in the absence of visible structural damage, strong ground shaking can significantly increase the risk of derailment if trains are travelling at high speed. For this reason, the main objective of EEW for railways is not to prevent damage itself, which cannot be avoided once strong shaking occurs, but to manage train operations in real time. By slowing down or stopping trains before they enter potentially damaged sections, EEW can substantially reduce accident risk and support safer post-event inspections (Figure 3). International experience has demonstrated both the feasibility and the complexity of this task. [caption id="attachment_10813" align="aligncenter" width="449"] Figure 3. Example of applications of EEWS to high-speed railways. Alerts provided by EEWS can be used to slow down trains travelling along the line, to avoid derailment or passing over damaged tracks (Image credit: Authors; produced by SciAni. Screenshots from the video “Earthquake early warning: how to and what for?)[/caption] Japan pioneered the integration of EEW into railway operations decades ago, protecting the Shinkansen network through automated responses [7, 8]. China has rapidly expanded similar capabilities alongside its extensive high-speed rail system [9, 10]. Urban and regional rail networks in other countries have also explored EEW-based control, including pilot integrations of the ShakeAlert system with transit operations in California (e.g., Bay Area Rapid Transit), as well as applications of EEW-enabled railway protection strategies developed in Taiwan [11,12]. In Euro-Mediterranean countries, feasibility studies and prototype implementations have developed the use of EEW for high-speed rail protection along the TGV Lyon–Marseille corridor [13] and for the Marmaray rail tunnel in Istanbul, where rapid train control following seismic alerts has been evaluated as a mitigation strategy [14].

From Research to Reality: Building an Early Warning System for Railways

This end-to-end philosophy lies at the heart of the first operational EEW system developed for a high-speed railway in Italy, on a pilot railway segment between Rome and Naples, a corridor of about 200 km that runs close to the central–southern Apennines, one of the most seismically active regions of the country [15]. At its core, the system relies on a dedicated network of accelerometric stations installed along the railway line, roughly every 10 km to measure rapid ground shaking during earthquakes. These stations are equipped with strong-motion accelerometers, that are instruments designed to measure rapid ground shaking during earthquakes. The sensors continuously record seismic-wave-triggered ground vibrations and transmit data in real time to a central processing unit. When an earthquake occurs, the system rapidly detects the first P waves and analyses the earliest portion of the recorded signals to predict the expected peak ground acceleration along the line. Rather than focusing on earthquake magnitude, the system adopts a threshold-based, shaking-forecast-oriented approach, centered on whether ground shaking is expected to exceed user-defined levels that require operational intervention. The system identifies in real-time the specific portion of the railway where strong shaking is expected to exceed the user-set threshold and defines the Alerted Segment of the Railway (ASR). Here, automatic train-blocking devices - fully integrated with the traffic control system – prevent trains approaching the alerted segment from entering it and trains already within it to decelerate and stop automatically (Figure 3). Crucially, the system is also designed to manage the end of the alert, using real-time strong-motion data to confirm when shaking has ceased and to support rapid, informed decisions on the resumption of normal operations.

Alerted Segments and Real Benefits: Measuring EEW in Practice

A key feature of the system is the quantitative evaluation of its performance and operational benefits. For extended targets such as railways, traditional EEW metrics based solely on magnitude estimation or single-site lead time and expected shaking level are insufficient. Instead, the system was assessed through a combination of massive numerical simulations and tests using real earthquake recordings from the 2016–2017 Central Italy seismic sequence [15]. Hundreds of synthetic earthquakes were simulated near a virtual railway line to explore a wide range of magnitudes, distances, and geometries, allowing researchers to systematically analyze alert timing, prediction accuracy, and the spatial extent of alerts. These simulations were complemented by real data to ensure realism and robustness. The results demonstrate that alerts can be issued within a few seconds from earthquake initiation (typically between three and ten seconds) and that the system correctly predicts whether shaking thresholds will be exceeded in most cases. By combining seismic scenarios with real traffic data from the Naples–Rome line, the study shows that for most realistic earthquakes only limited portions of the line require restrictions, and most trains can be managed efficiently without unnecessary disruption. Even when trains are already within the alerted segment, early deceleration can significantly reduce risk. Very large earthquakes close to the line would affect longer segments, but such earthquake scenarios have historically very long return periods. Beyond immediate safety, the system also provides near-real-time strong-motion information that can be used to map potentially damaged sections of the infrastructure, supporting faster and more targeted post-earthquake inspections of the railway. Designed with scalability and adaptability in mind, the system can be exported to other railway lines and integrated with different seismic networks. In this sense, the Italian experience represents not only a national first, but also a reference model for transforming Earthquake Early Warning from a scientific capability into a concrete, operational tool for protecting critical infrastructure and enhancing societal resilience.

References

[1] Kanamori, H., 2005. Real-time seismology and earthquake damage mitigation, Annu. Rev. Earth Planet. Sci., 33, 195–214, https://doi.org/10.1146/annurev.earth.33.092203.122626,. [2] Satriano, C., Wu, Y. M., Zollo, A., and Kanamori, H..2011. Earthquake early warning: Concepts, methods and physical grounds, Soil Dynamics and Earthquake Engineering, 31, 106–118, https://doi.org/10.1016/j.soildyn.2010.07.007. [3] Allen, R.M., Gasparini, P., Kamigaichi, O., Bose, M., 2009. The Status of Earthquake Early Warning around the World: An Introductory Overview. Seismological Research Letters 80, 682–693. https://doi.org/10.1785/gssrl.80.5.682 [4] Allen, R. M. and Melgar, D., 2019. Earthquake early warning: Advances, scientific challenges, and societal needs, Annu. Rev. Earth Planet. Sci., 47, 361–388, https://doi.org/10.1146/annurevearth-053018-060457, 2019. [5] Espinosa-Aranda, J.M., Cuellar, A., Garcia, A., Ibarrola, G., Islas, R., Maldonado, S., Rodriguez, F.H., 2009. Evolution of the Mexican Seismic Alert System (SASMEX). Seismological Research Letters 80, 694–706. https://doi.org/10.1785/gssrl.80.5.694 [6] Clinton, J., Zollo, A., Marmureanu, A., Zulfikar, C., Parolai, S., 2016. State-of-the art and future of earthquake early warning in the European region. Bulletin of Earthquake Engineering 14, 2441–2458. https://doi.org/10.1007/s10518-016-9922-7 [7] Yamamoto, S. and Tomori, M.: Earthquake Early Warning System for Railways and its Performance, Journal of JSCE, 1, 322–328, https://doi.org/10.2208/JOURNALOFJSCE.1.1_322, 2013. [8] Iwata, N., Yamamoto, S., Korenaga, M., and Noda, S.: Improved Algorithms of Seismic Parameters Estimation and Noise Discrimination in Earthquake Early Warning, Quarterly Report of RTRI, 56, 291–298, https://doi.org/10.2219/RTRIQR.56.4_291, 2015. [9] Tan, M., Hu, Q., Wu, Y., Lin, J., and Fang, X.: Decision-making method for high-speed rail early warning system in complex earthquake situations, Transportation Safety and Environment, 6, https://doi.org/10.1093/TSE/TDAD034, 2024. [10] Zhang, G., Yang, L., and Jiang, W.: Key technologies of earthquake early warning system for China's high-speed railway, Railway Sciences, 3, 239–262, https://doi.org/10.1108/RS-11-2023-0046, 2024. [11] Strauss, J.A., Allen, R.M., 2016. Benefits and Costs of Earthquake Early Warning. Seismological Research Letters 87, 765–772. https://doi.org/10.1785/0220150149 [12] Wu, Y.-M., Kanamori, H., 2008. Development of an Earthquake Early Warning System Using Real-Time Strong Motion Signals. Sensors 8, 1–9. https://doi.org/10.3390/s8010001 [13] GeoSig Ltd, 2026. CaseStudy_TGV_HighSpeedRailway_France (Open File Report), EEW - Case Studies (https://www.geosig.com/files/CaseStudy_TGV_HighSpeedRailway_France.pdf) [14] Alcik, H., Ozel, O., Apaydin, N., Erdik, M., 2009. A study on warning algorithms for Istanbul earthquake early warning system. Geophysical Research Letters 36, 2008GL036659. https://doi.org/10.1029/2008GL036659 [15] Colombelli, S., Zollo, A., Carotenuto, F., Caruso, A., Elia, L., Festa, G., Gammaldi, S., Iaccarino, A. G., Iannaccone, G., Mauro, A., Picozzi, M., Polimanti, G., Riccio, R., Tarantino, S., Cirillo, F., Vecchi, A., and Iacobini, F.: The first Earthquake Early Warning System for the high-speed railway in Italy: enhancing rapidness and operational efficiency during seismic events, Nat. Hazards Earth Syst. Sci., 26, 299–314, https://doi.org/10.5194/nhess-26-299-2026, 2026. Post edited by: Hedieh Soltanpour and Navakanesh M Batmanathan

Memories from the Field - The Vastness of the Greenland Ice Sheet

Sophie Berger — Mon, 16 Mar 2026 13:17:21 +0000

I remember the day very well. It was the first time we drove up to the glacial ice from our base station in Kangerlussuaq (Western Greenland), where we had patiently been waiting for two days for the weather to clear. I took this photo during a three-week fieldwork campaign in July of 2025 as part of the Deep Purple project. As part of the project, we were in the field to collect glacial ice-algae samples, which grow on (and thereby darken) ice surfaces. The grey fog finally lifted, and our patience was rewarded with bright blue sky and sunshine that made the small blue meltwater rivers sparkle. I recall the crunch of the ice below my feet and how we walked up one of the small hills which followed one other all the way to the horizon. We were still very close to the margin of the glacier, and had only walked a couple hundreds of meters from the moraines where we parked our car, but when I faced inland, the ice spread out into a stunning vastness that is hard to capture in a photo. Behind each of the hills --some steep with almost-sharp ridges, some gently rounded-- we found something new: shallow blue lakes with sediment covering the bottom, whooshing rivers, the glisten of clean ice and cryoconite holes of all sizes. I remember the brightness of the landscape, so bright that it hurt the eyes, the cold of the wind, and how all I could hear was the wind, the water and my own breath. When we turned around to walk back to the car, it felt like coming back from a different planet. Just as soon as I stepped off the ice, I already began to look forward to returning to this beautiful, wild, and humbling vastness.

Edited by Mack Baysinger

Highlighting: Martian Geomorphology (Interview with Lauren Mc Keown)

annavdb — Mon, 16 Mar 2026 13:31:05 +0000

This blog post is part of our series: “Highlights” for which we’re accepting contributions! Please contact Emma Lodes and Anna van den Broek (GM blog editor, elodes@asu.edu, a.j.vandenbroek@uu.nl), if you’d like to contribute on this topic or others. by Lauren Mc Keown, Assistant Professor - University of Central Florida. Email: Lauren.Mc.Keown@ucf.edu. Website: http://www.laurenemckeown.com/. [caption id="attachment_2799" align="alignnone" width="300"] Photo of Lauren (PC: Lauren Mc Keown).[/caption]

What is interesting about the geomorphology of Mars? Martian geomorphology is interesting because there are a whole host of features that formed via the interaction between the surface and atmosphere, or surface and subsurface, that areindicative of the environment under which they formed, regardless of geological time period. I am mostly interested in features that formed very recently or are still evolving in the present day. To me, the fact that the Martian surface is active seasonally today and that we can observe changes over short timescales is fascinating. I find it especially exciting that by studying these active features, we can link specific landforms to the processes shaping the planet right now and gain insight into how Mars’ current climate influences its landscape. I am also particularly fascinated by surface expressions and dynamics that have no direct analogs on Earth, such as `spiders’ which are radial networks of dendritic troughs detected around the Martian South Pole proposed to form by the seasonal sublimation of translucent CO₂ slab ice and the Solid State Greenhouse Effect, and linear dune gullies, which are linear or sinuous channels found on Martian sand dunes that terminate in circular pits and are proposed to form by levitating sliding CO₂ ice blocks in spring.

[caption id="attachment_2800" align="aligncenter" width="840"] A spider that has formed on Mars (Latitude (centered)
-73.162°, Longitude (East) 330.399; PC: NASA/JPL-Caltech/UArizona).[/caption]

What are the similarities and big differences in the geomorphology of the Earth?

Mars and Earth share some common processes. For example, wind drives sediment transport on both planets producing dunes and ripples, and freeze‑thaw or frost effects can produce patterned ground in cold regions on Earth similar to Martian analogs. However, the atmospheric conditions, volatile inventory, and surface temperatures are very different on Mars; seasonal CO₂ frost and sublimation play dominant roles in shaping its surface that simply don’t operate here. As a result, many Martian landforms, such as CO₂‑venting `spiders’ (my favourite feature!) or linear gullies linked to dry ice processes, have no direct terrestrial analogues.

Can you describe in about 3 sentences what the main objective of your research on Mars is?

My research aims to understand how volatile phase‑change processes like the seasonal sublimation of CO₂, water sublimation and transient brine activity, shape Martian landscapes. I combine high‑resolution orbital imagery with laboratory analog experiments that simulate Martian conditions to investigate how these processes operate and evolve. Ultimately, I want to link observable landforms to specific environmental conditions to reveal how the present-day Martian surface is actively changing.

[caption id="attachment_2796" align="alignleft" width="300"] Lauren cooling samples for Martian spider experiments in front of DUSTIE (PC: Lauren Mc Keown).[/caption] Since you can’t do fieldwork on Mars, what is your favorite method to research its geomorphology? Since we can’t conduct fieldwork on Mars, one of my favorite ways to study its geomorphology is through laboratory experiments that simulate Martian conditions. In thermal-vacuum planetary simulation chambers, we can recreate aspects of the Martian environment, such as low atmospheric pressure, cold temperatures, and the presence of CO₂ ice, as well as observe how granular materials and phase changes of volatiles interact under those conditions. These experiments allow us to test specific hypotheses about how landforms form and evolve, which helps us interpret the features we see in orbital imagery of Mars, for example, Martian spiders, linear dune gullies or pits found at the center of possible ice-rich impact craters. Of course, such experiments are limited by scale, but this evolving area of research is revealing paradigm-shifting insights about how the behavior of volatiles is modifying the surface of Mars. By combining laboratory results with modeling and remote sensing observations, we can better understand the physical processes actively shaping the Martian surface today. What would be an amazing improvement to the method? There are many PI-led labs now that are doing excellent research on icy planetary analog geomorphology - equally, the engineers who developed the rovers on Mars, in particular the sample acquisition systems, have key knowledge of surface properties and how ices interact with regolith on planetary surfaces. During my time at JPL, I worked at the intersection of science and engineering with these experts and the science that I pursued there directly benefited from cross-collaboration. Furthermore, I collaborated with astrobiologists regarding how geomorphology studies may indicate near-surface conditions for life on icy moons - that work would not have been possible without expertise that was not my own. I believe that facilitating intersectional approaches through communication avenues, networking at international conferences as well as funding will help develop the growing field of laboratory analog planetary geomorphology. New ideas and perspectives are critical to understanding the present-day environment on Mars, especially if we eventually send humans there who need local water resources, as well as to be protected from natural hazards. I want to emphasize that we must also be open to new approaches and perspectives that have not been tried before - some of the work I am most proud of developed in creative environments where I felt safe to share an 'out there' idea.

How can what you learned about Mars be applied elsewhere?

Mars is an excellent natural laboratory 'on our doorstep' in the Solar System for understanding icy surfaces elsewhere, including on icy moons and small bodies. With the HiRISE and CTX cameras onboard the Mars Reconnaissance Orbiter, we can see how seasonal ice depositing and warming up affects the surface in real time. The tools and insights from Martian [caption id="attachment_2795" align="alignright" width="300"] A dendritic `star-like’ pattern formed in the Europa granular ice simulant when water flowed through it under cold simulated post-impact conditions in the lab (PC: Lauren Mc Keown).[/caption] geomorphology research help us understand how volatile‑driven processes operate under extreme conditions. When active gullies and Recurring Slope Linae were found on Martian slopes for example, connection with similar features formed on Earth by liquid water-assisted debris flow posed a problem - how could water flow at the low pressures and temperatures of present-day Mars? Theoretically, this was not possible, except for at limited ranges. So followed an advent of experimental work investigating how exactly liquid water behaves under limited circumstances on Mars today and colleagues discovered all sorts of weird and wonderful phase change dynamics such as levitating water pellets (Raack et al., 2017), that actually have vast geomorphic agency under low pressure regimes. Since then, similar insights have been gained via analog lab experiments I was fortunate to be involved with investigating gullies on small bodies (Poston et al., 2024) - we found that even under post-impact far lower pressure conditions than on Mars, water could exist as liquid for up to an hour! Further experimental work that I led regarding a potentially liquid-water driven star-like feature on Europa (Mc Keown et al., 2025) explored the role of transient brine activity under extremely low temperature conditions, finding the spread of water through slush can melt dendritic patterns similar to Earth’s lake stars. That brings me full-circle to Earth and the importance of analog field geomorphology in understanding how granular materials and seasonal frosts interact on Mars and other planetary surfaces - a whole host of research has benefited from our knowledge of cold‑climate landforms and highlights fundamental geomorphic principles that apply across environments, despite different driving boundary conditions; from periglacial terrain like polygonal patterned ground, to gullies, to lake stars on Earth’s frozen lakes and ponds, comparative planetology is a fascinating approach that helps us understand icy surfaces in our solar system much better.

Is there anything you would like to add?

One of the most exciting aspects of planetary geomorphology today is that we can observe active surface processes remotely and then test our hypotheses physically in the laboratory, bridging observational science with experimental simulations and in turn learning how physical processes behave very differently on planetary surfaces. My work at the University of Central Florida, in collaboration with NASA and other institutions, is revealing surprising insights about how landscapes evolve under conditions very different from Earth’s. I’m currently building a laboratory called the Facility for Research Observing Simulated Topography of Icy Environments (FROSTIE) where we work with thermal-vacuum chambers that simulate planetary surfaces, as well as develop and analyze icy planetary surface simulants to understand these processes more. I am passionate about mentoring students and communicating this science, because these discoveries reshape how we understand other worlds and our place in the solar system.

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