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Meet the experts: The future of solar-terrestrial research

Meet the experts: The future of solar-terrestrial research

This year’s General Assembly saw more Short Courses than ever before! With many of the 50 courses on offer having been organised by and/or for early career scientitst, there was no excuse not to pick up some new skills. In this guest blog post, Jone Peter Reistad a PhD candidate at the University of Bergen, outlines the details of a session which explored what the future might hold for research in the Solar- Terrestrial sciences. With active discussion between established and early career scietists this course was no doubt a hit.

During the General Assembly a new short course took place: Meet the Experts – The Future of Solar-Terrestrial Research. In this session, three senior scientists as well as two Early Career Scientists (ECS) were invited to talk about their visions for the future of the Solar-Terrestrial sciences. They were given the difficult task of identifying important challenges within their field of expertise that the present young scientists need to address in the future.

The speakers came from the different communities within the solar-terrestrial division. This included the solar-, heliospheric-, and the near Earth space communities. They all did an outstanding job in pointing out challenges and knowledge gaps within their field.

Starting at the Sun, Louise Harra, Professor of solar physics at University College London, pointed out how much more we know today due to all the recent solar missions. She assured us that more is definitely to come, as new missions are already in the pipe-line, and encouraged the young scientists to get involved in these future missions at an early stage. She had lots of ideas of what to look for with more precise instruments, and pointed out that a key to understand the evolution of the structures observed at the surface of the Sun is to be able to model the evolution of the structures below the surface using helioseismology.

From the Heliospheric community, emphasis was put on the more recent ability to track evolution of hot gases all the way from the Sun to the Earth. Alexis Rouillard, researcher at the French National Centre for Scientific Research, told us that the recent satellite missions had contributed to strengthen the bonds between the Solar and Heliospheric communities so that the two now uses a more common terminology. This was a tendency he very much hoped to see continuing into the future.

The crucial link to Space Weather applications is the ability to predict the orientation of the magnetic field originating from the Sun when it reaches the Earth. This is by far the most uncertain factor in modeling the geomagnetic impact of a solar storm. Rouillard discussed how having a satellite closer to the Sun could possibility enhance our understanding of this propagation and hence revolutionise space weather predictions in the future.

Yuri Shprits, speaking at the session about the  future of solar-terrestrial research. (Credit:  Christer van der Meeren, Birkeland Centre for Space Science, University of Bergen)

Yuri Shprits, speaking at the session about the future of solar-terrestrial research. (Credit: Christer van der Meeren, Birkeland Centre for Space Science, University of Bergen)

Space Weather – the impact on the near Earth space from the outside – was also discussed from a more Earth-centered perspective. Communication through space-based instrumentation becomes increasingly important as more and more infrastructure is becoming dependent on satellite communications. A detailed knowledge of the mechanisms that influence our communications are therefore more important now than ever. Yuri Shprits, researcher at MIT and UCLA, emphasized that the Earths radiation belts is a key region, and that there are still open questions regarding their buildup and loss mechanisms.

This short course was a result of feedback from last years survey among Early Career Scientists in EGU. The short courses at EGU was highlighted as one of the most important activities that was directly targeting the ECS’s. As each division in EGU has their own ECS representative, you can influence the division specific activities for young scientists by contacting your respective ECS representative. Visit https://www.egu.eu/young-scientists/ for more information about the Early Career Scientist activity within the EGU.

 

By Jone Peter Reistad, PhD Candiadte at the University of Bergen.

Imaggeo on Mondays: Foehn clouds

This week’s post is brought to you by Stefan Winkler, a Senior Lecturer in Quaternary Geology & Palaeoclimatology, who explains how the mountain tops of the Southern Alps become decorated by beautiful blanket-like cloud formations.

The Sothern Alps of New Zealand are a geoscientifically dynamic environment in all aspects. They are arguably one of the youngest high mountain ranges in the world formed at the plate tectonic boundary between the Australian and the Pacific Plate. Their dominating tectonic structure, the Alpine Fault running some 600 km mainly parallel to the mountain ranges of New Zealand’s South Island, caused not only an impressive horizontal displacement of rock formations, but also an overall vertical uplift of estimated c. 20 km during the past 10 – 15 Million years. Aoraki/Mt.Cook visible in the left background on the image with its height of ‘only’ 3724 m a.s.l. is the highest peak of the mountain range that is currently uplifted by 4 – 5 mm per year. Together with reconstructed uplift rates of up to 10 mm per year for the centre of the Southern Alps this indication how efficient and important weathering and erosion processes are in this region.

Foehn clouds over Aoraki/Mt.Cook. Credit: Stefan Winkler (distributed via imaggeo.egu.eu)

Foehn clouds over Aoraki/Mt.Cook. Credit: Stefan Winkler (distributed via imaggeo.egu.eu)

The ranges of the Southern Alps rise just 10 – 15 km inland the West Coast of the South Island as a wall parallel to the coast line up to 3,000 metres and more. They are a major topographic obstacle for the predominantly westerly airflow and provide a classic example of how ‘föhn’ winds are generated along mountain ranges perpendicular to an air flow. Föhn winds are dry and warm, forming on the downside of a mountain range. On the western slopes of the Southern Alps, orographic precipitation amounts to impressive 5,000 mm at the base and 10,000 mm + on in the high-lying accumulation areas of the mountain glaciers concentrating around the Main Divide. At and east of the Main Divide this locally named ‘Nor’wester’ creates impressive foehn clouds (altocumulus lenticularis, hogback clouds, seen in this week’s Imaggeo on Mondays image) that form in waves parallel to the Main Divide and are often streamlined by the high wind speed. The frequent occurrence of strong and warm Nor’westers contributes to the sharp decline of precipitation immediately east of the Main Divide.

The foreground of the image displays another aspect of this dynamic environment: the current wastage and retreat of glaciers in New Zealand. The section of the proglacial lake with its sediment-laden greyish water colour on the image would still have been covered by the debris-covered lower glacier tongue of Mueller Glacier only 15 years ago. Now, the terminus has retread to a position to the left outside the image. The lake is bounded by the glacier’s lateral moraine – unconsolidated accumulations of rock and soil debris resulting from weathering of the rock walks surrounding a glacire – that are more than 120 m high from base to top (or crest, to give it its technical name) and were last overtopped during the so-called ‘Little Ice Age’ when the glacier surface reached higher than its crest. At this glacier, the maximum of this Little Ice Age has been dated to 1720/30, but as late as during the late 20th century it remained close to its frontal maximum position and had only shrunk vertically. Today the lateral moraines are heavily reworked and eroded by paraglacial processes following the latest vertical and horizontal ice retreat. In some places on Mueller Glacier’s foreland the crest of lateral moraines retreat up to 1 m per year back and give again evidence of a very dynamic geo-ecosystem.

By Stefan Winkler, Senior Lecturer in Quaternary Geology and Palaeoclimatology at the Univeristy of Canterbury.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Iceland’s Bárðarbunga-Holuhraun: a remarkable volcanic eruption

Iceland’s Bárðarbunga-Holuhraun: a remarkable volcanic eruption

A six month long eruption accompanied by caldera subsidence and huge amounts of emitted gasses and extruded lavas; there is no doubt that the eruption of the Icelandic volcano in late 2014 and early 2015 was truly remarkable. In a press conference, (you can live stream it here), which took place during the recent EGU General Assembly, scientists reported on the latest from the volcano.

Seismic activity in this region of Iceland had been ongoing since 2007, but in late August 2014 a swarm of earthquakes indicated that the activity at Bárðarbunga-Holuhraun was ramping up a notch. By August 18th, over 2600 earthquakes had been registered by the seismometer network, ranging in magnitude between M1.5 and M4.5. Scientist now know that one of the main drivers of the activity was the collapse of the ice-filled Bárðarbunga caldera.

Caldera collapses -where the roof of a magma chamber collapses as a result of the chamber emptying during a volcanic eruption – are rare; there have only been seven recorded events this century. The Bárðarbunga eruption is the first caldera collapse to have occurred in Iceland since 1875. They can be very serious events which result in catastrophic eruptions (e.g. the Toba eruption of 74,000 BP). In other cases the formation of the large cauldron happens over time, with the surface of the volcano slowly subsiding as vast amounts of magma are drained away via surface lava flows and the formation of dykes. Bárðarbunga caldera subsided slowly and progressively, much more so than is common for this type of eruption, to form a depression approximately 8km wide and 60m deep.

“The associated volcanic eruption, which took place 40km away from the caldera, was the largest, by volume and mass of erupted materials, recorded in Iceland in the past 230 years”, described Magnus T. Gudmundsson, Professor at the Institute of Earth Sciences at the University of Iceland, during the press conference.

If the facts and figures above aren’t sufficiently impressive, the eruption at Holuhraun also produced the largest amount of lava on the island since 1783, with a total volume of over 1.6 km3 and stretching over more than 85 km4. In places, the lava flows where 30 m thick!

The impressive figures shouldn’t detract from the significance of the events that took place during those six months: scientists were able to observe the processes by which new land is made on Earth! Major rifting episodes like this “only happen once every 50 years or so”, explained Gudmundsson.

So what exactly have scientists learnt? Most divergent boundaries – where two plates pull apart from one another – are found at Mid-Ocean Ridges, meaning there is little opportunity to study rifting episodes at the Earth’s surface. The eruption at Bárðarbunga-Holuhraun offered researchers the unique opportunity to take a closer look at how rifting takes place; something which so far has only been possible at the Afar rift in Ethiopia.

New crust is generated at divergent plate margins, commonly fed by vertical sheet dykes – narrow, uniformly thick sheets of igneous material originating from underlying magma chambers. Dykes at divergent plate boundaries are common because the crust is being stretched and weakened. One of the clusters of seismic activity at Bárðarbunga-Holuhraun was consistent with the formation of a dyke. The seismic signal showed that the magma from the Bárðarbunga caldera, rather than being transported vertically upwards to the surface, was in fact being transported laterally, forming a magma filled fissure which stretched 45 km away from Bárðarbunga. This video, from the Icelandic Met Office, helps to visualise the growth of the dyke over time.

The figure shows all the earthquakes which took place in the region in and around Bárðarbunga, from 16 August 2016 until 3 May 2015. The bar on the right counts days since the onset of events, and it gives a colour code indicative of the time passed. The dark blue colour implies the oldest earthquakes whereas the red colour implies the youngest earthquakes. The earthquakes clearly show the growth of a lateral dyke, headed northeast, away from the Bárðarbunga caldera. Click here to enlarge the map. (Credit: Icelandic Meteorological Office)

The figure shows all the earthquakes which took place in the region in and around Bárðarbunga, from 16 August 2016 until 3 May 2015. The bar on the right counts days since the onset of events, and it gives a colour code indicative of the time passed. The dark blue colour implies the oldest earthquakes whereas the red colour implies the youngest earthquakes. The earthquakes clearly show the growth of a lateral dyke, headed northeast, away from the Bárðarbunga caldera. Click here to enlarge the map. (Credit: Icelandic Meteorological Office)

Further study of the dyke using understanding gained the from propagating seismicity, ground deformation mapped by Global Positioning System (GPS), and interferometric analysis of satellite radar images (InSAR), allowed scientists to observe how the ground around the dyke changed in height and shape. The measurements showed the dyke was not a continuous feature, but rather it appeared broken into segments which had variable orientations. Modelling of the dyke revealed that it was the interaction of the laterally moving magma with the local topography, as well as stresses in the ground cause by the divergent plates, that lead to the unusual shape of the dyke.

On average, magma flowed in the dyke at a rate of 260 m3/s, but the speed of its propagation was extremely variable. When the magma reached natural barriers, it would slow down, only picking up momentum again once pressure built up sufficiently to overcome the barriers. Shallow depressions observed in the ice of Vatnajokull glacier (the white area in the map above) – known as Ice cauldrons – were caused by minor eruptions underneath the ice at the tips of some of the dyke segments. The dyke propagation slowed down once the fissure eruption at Holuhraun started in September 2014.

What has the Bárðarbunga-Holuhraun taught scientists about rifting processes? It seems that at divergent plate boundaries, in order to create new crust over long distances, magma generated at central volcanoes (in this case Bárðarbunga), is distributed via segmented lateral dykes, as opposed to being erupted directly above the magma chamber.

 

By Laura Roberts Artal, EGU Communications Officer

 

Further reading and references

You can stream the full press conference here: http://client.cntv.at/egu2015/PC7

Details of the speakers at the press conference are available at: http://media.egu.eu/press-conferences-2015/#volcano

The speakers at the press conference also reported on the gas emissions as a result of the Holuhraun fissure eruption and the implications for human health. You can read more on this here: Bardarbunga eruption gases estimated.

Sigmundsson, F., A. Hooper, Hreinsdóttir, et al.: Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland, Nature, 517, 191-195, doi:10.1038/nature1411, 2015.

Sigmundsson, F., A. Hooper, Hreinsdóttir, et al.: Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland, Geophys. Res. Abstr.,17, EGU2015-10322-1, 2015 (conference abstract).

Hannah I. Reynolds, H. T., M. T. Gudmundsson, and T. Högnadóttir: Subglacial melting associated with activity at Bárdarbunga volcano, Iceland, explored using numerical reservoir simulation, Geophys. Res. Abstr.,17, EGU2015-10753-2, 2015 (conference abstract).

Upload your 2015 General Assembly presentation

Upload your 2015 General Assembly presentation

This year it is once again possible to upload your oral presentations, PICO presentations and posters from EGU 2015 for online publication alongside your abstract, giving all participants a chance to revisit your contribution  hurrah for open science!

Files can be in either PowerPoint or PDF format. Note that presentations will be distributed under the Creative Commons Attribution 3.0 Licence. Uploading your presentation is free of charge and is not followed by a review process. The upload form for your presentation, together with further information on the licence it will be distributed under, is available here. You will need to log in using your Copernicus Office User ID (using the ID of the Corresponding Author) to upload your presentation.

Presentations and posters will be linked to from their corresponding abstracts. If your presentation didn’t have an abstract (this is the case for Short Courses and others), but you still want to share it with the wider community you can consider uploading your presentation to slideshare or figshare as a PDF to share it instead.

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