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Imaggeo on Mondays: High above the top of Europe

Imaggeo on Mondays: High above the top of Europe

Sentinel-2B imaged the highest mountains of western Europe, just the moment an airplane was about to fly over the granite peaks of Grandes Jorasses and cross the border from France to Italy. The passengers on the right side of the plane must have enjoyed a spectacular view on Mont Blanc, just nine kilometers away to the south-west, and Mer de Glace, the longest glacier in France flowing down from its peak.

Note the shadow of the granite “aiguilles” on fresh early winter snow in the upper part of the glacier. The famous Aiguille de Midi is casting its shadow on the village of Chamonix on the top-left, as late autumn colours are still visible on the larch in Val Ferret in the bottom-right corner of the image. Contains Copernicus Sentinel data (2018). Processed with Sentinelflow (v0.1.3).

Description by Julien Seguinot, as it first appeared on imaggeo.egu.eu.

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/.

Imaggeo on Mondays: Northern lights in northern Norway

Imaggeo on Mondays: Northern lights in northern Norway

Northern lights in Tromsø, displaying the collisions between electrically charged particles from the sun which penetrate the earth’s magnetic shield and strike atoms and molecules in our atmosphere. Collisions excite the atoms causing electrons to move to higher-energy orbits, further away from the nucleus. When electrons move back to lower-energy orbits, they release particles of light called photons which form the aurora. The green color is produced by collisions with oxygen, purple colors are produced by collisions with nitrogen.

Description by Rita Nogherotto, as it first appeared on imaggeo.egu.eu.

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/.

Imaggeo on Mondays: Patterns in the peatland

Imaggeo on Mondays: Patterns in the peatland

This magnificent pattern is the result of hundreds and hundreds of years of evolution. In this structured minerotrophic peatland in Northern Quebec (Canada), which can also be called a string fen or aapa mire, the green peat ridges (or strings) alternate with water-filled hollows (or flarks). Often flarks are replaced by ponds, which vary in number and size. This pattern of strings and flarks (or ponds) runs perpendicular to the flow of ground water.

Many theories exist to explain the dynamics of this pattern; however, we still do not know the mechanism responsible. Almost all of the present theories suggest that the movement of water could be a major driver of the landscape’s features. The permafrost and frost action, the gradual down-slope slipping, and expansion of peat, the merging of hollows, and fire outbreaks are also considered to be potential factors. Further research is going on to deeply understand the complex relation between abiotic and biotic factors influencing how the string fens take shape.

Vegetation in string fens differs between strings and flarks. Strings are dominated by sedges like Carex exilis, Trichophorum cespitosum, Eriophorum angustifolium, and dwarf birches (Betula glandulosa). On the other hand, flarks or ponds are dominated by Menyanthes trifoliata (also known as bogbean), depending on the level of the water within the ground. The peat moss Sphagnum subfulvum is found on strings while a different species of moss Sphagnum majus can be found on floating mats, at the margin of ponds.

This type of peatland is abundant in the boreal regions of the world, and its predominance can be explained by cooler weather conditions, that limit Sphagnum growth and foster greater surface water flow, especially when the snow melts in the spring.

I encountered this beauty on a field trip during summer of 2016 when I was looking for fens burned by natural wildfires. Unfortunately (or not) this one did not burn, even though all the forests at the margin of the peatland burned pretty heavily. Indeed, the ground of the burned forests was covered by Polytrichum strictum, a pioneer moss known to colonize burned forests or peatland soils (look for the apple green vegetation in the bottom of the photograph).

By Mélina Guêné-Nanchen, Laval University, Québec, Canada

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/.

Imaggeo on Mondays: Air samples from afar

Imaggeo on Mondays: Air samples from afar

I’ve taken many photos on fieldwork, everywhere from Malaysia to Antarctica but this particular photo was taken in my ‘home’ lab at the University of East Anglia (UEA) in Norwich, UK. Atmospheric scientists collect air samples canisters such as these from around the world: from high altitude research aircraft (such as the Geophysica), long-term measurement time series (such as Cape Grim) or field campaigns in urban and rural environments.

At UEA we measure these whole air samples for a suite of up to 50 trace gases, covering all the major ozone depleting substances and non-CO2/CH4 greenhouse gases. We measure compounds at ‘parts per trillion’ (ppt) level or below in samples as small as 20 ml. It’s very hard to visualise 1 ppt… but it’s equivalent to about one second in 32,000 years measured in a sample that could fit in an egg cup.

Often these air samples are also analysed at other labs in Europe and other parts of the world, adding to the total number of compounds and isotopes we can quantify. Samples such as these have helped us identify new threats to ozone recovery and to quantify emissions of climatically-important trace gases such as HFCs and PFCs. To measure such trace, trace gases requires an instrument that is both large and temperamental. As such, it doesn’t (well can’t) leave the lab and we bring all the samples back to it. Stopping to imagine where the samples came from and how rare and special they can be (air from 30 km high or from deep in an ancient ice core!) helps me get through the long and labour intensive days in the laboratory.

By Emma Elvidge, University of East Anglia, UK

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/.