CR
Cryospheric Sciences

Sophie Berger

Sophie Berger is a PhD student of the glaciology unit, at the Université Libre de Bruxelles (ULB), Brussels Belgium. She is using various remote sensing data and techniques to investigate the dynamics and stability of the ice shelves in Dronning Maud Land (East Antarctica). She tweets as @SoBrgr.

Image of the Week — Greetings from Antarctica

Image of the Week — Greetings from Antarctica

Christmas greetings from people at Rothera Research Station, Adelaide Island, Antarctica.

Rothera, which is the British Antarctic Survey’s largest base in Antarctica, is a centre for marine biology and gateway for getting scientists into their deep field camps.

Christmas Day is a regular working day for the staff of around 90. However the chefs will be getting everyone into the festive spirit with a traditional turkey dinner with all the trimmings

Image of the Week — AGU Fall Meeting 2015

Image of the Week — AGU Fall Meeting 2015

The American Geophysical Union (AGU) Fall Meeting, which takes place every December in  San Francisco is ending today.

With more than 24 000 attendees, 14 000 poster presentations and 7 000 talks, the AGU meeting is the largest conference on geophysical sciences in the World.

The cryosphere is one the topics covered by the meeting and we hope that this year edition was a fruitful for every participant.

Busy poster session on the Cryosphere. (Credit: Konstantinos Petrakopoulos)

Busy poster session on the Cryosphere. (Credit: Konstantinos Petrakopoulos)

 

Image of the Week — Future Decline of sea-ice extent in the Arctic (from IPCC)

Image of the Week — Future Decline of sea-ice extent in the Arctic (from IPCC)

The Arctic sea-ice extent has declined in the past 20 years and its future is uncertain. In the end, greenhouse gas emissions will determine the impact on the sea-ice from man-made climate change through radiative forcing (i.e. Representative Concentration Pathways or RCPs). The COP21 can determine the path we will follow and which course we will take to reduce emissions.

Reduction in sea-ice cover ranges from 43% (RCP 2.6) to 94% (RCP 8.5) in the period 2081-2100 compared to 1986-2005.

Why is sea important?

Decrease in sea-ice extent would:
– decrease the albedo of the Arctic ocean, therefore more heat would be absorbed by the ocean which would enhance the warming in this region.
– affect the global oceanic circulation as sea-ice formation influences the density of ice masses, which drives oceanic circulation.
– completely alter the ecosystem in the Arctic.

 

Further Reading

Stocker, T F, D Qin, G.-K. Plattner, L V Alexander, S K Allen, N L Bindoff, F.-M. Bréon, et al. 2013. “Technical Summary.” In Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, edited by T F Stocker, D Qin, G.-K. Plattner, M Tignor, S K Allen, J Boschung, A Nauels, Y Xia, V Bex, and P M Midgley, 33–115. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press. doi:10.1017/CBO9781107415324.005.

Read about sea ice and its importance on the NSIDC website

 

Previous blog posts featuring sea-ice science:

Do beers go stale in the Arctic?

Cruising for mud sediments from the ocean floor

Camping on the Svalbard coast

Image of the Week: Under the sea

Image of the Week — Ice Sheets and Sea Level Rise (from IPCC)

Image of the Week — Ice Sheets and Sea Level Rise (from IPCC)

Context

On the eve of the COP21, it is of paramount importance to recall how strongly the cryosphere is affected by Climate Change. Today, we present the impact of melting ice on sea level rise, as it is presented in the latest assessment report of the Intergovernmental Panel on Climate Change.

Quick facts

-Since 1992, the Glaciers, Greenland and Antarctic Ice Sheets have risen the sea level by 14, 8 and 6 mm, respectively.
-The Greenland and Antarctic ice losses have accelerated for the last 2 decades.
In Greenland ice-loss rates increased from 34 Gt/yr* (between 1992-2001) to 215 Gt/yr (between 2002-2011), which was caused by more widespread surface melt + run-off and enhanced discharge of outlet glaciers.
While in Antarctica, ice-loss rates “only” rose from  30 Gt/yr (between 1992-2001) to 147 Gt/yr (between 2002-2011), this loss mostly occurred in West Antarctica (Amundsen Sea Sector and Antarctic Peninsula) and  was driven by  the acceleration of outlet glaciers.

 

*An ice loss of 100 Gt/yr is approximately 0.28 mm/yr of sea level equivalent

Further Reading [Read More]

Image of the Week: Under the Sea

Image of the Week: Under the Sea

Always wondered how it looks like under the sea ice?
Getting an answer is simpler than you might think: Just go out to the front of McMurdo ice shelf in Antarctica and drill a tube into the sea ice. Then let people climb down and take pictures of the ice from below.
More information:
– Photo taken by Marcus Arnold, Gateway Antarctica, University of Canterbury during his November 2015, Antarctic Expedition.
– More photos of their expedition on https://instagram.com/the_ross_ice_shelf_programme/

Image of the Week — What’s up with the sea-ice leads?

Image of the Week — What’s up with the sea-ice leads?

This illustration shows two Synthetic Aperture Radar (SAR) images taken over sea ice in the Arctic Ocean. Both images are polarimetric and the different colours reflect the different polarimetric channels of the SAR (red = VV, green = HV and blue = HH).

The two images are from the two satellites “ALOS-2” and “RADARSAT-2”. These are equipped with radars that operate at wavelengths around 24 cm and 6 cm, respectively. As can be seen, certain types of sea ice appear very different due to this difference in radar wavelength. In particular, leads in the ice, that is, open or refrozen cracks, appear very red for the longer wavelength, but dark for the shorter wavelength. A full understanding of what causes these differences is still not complete, but could help monitor ice properties, such as thickness and salinity, with satellites. These properties are in turn crucial for climate scientists.

 

Click on the image to see difference between the two images. (Credit: J. Grahn)

Further information see : Grahn et al. 2015, Proceedings of “ESA PollinSAR 2015”

 

Credits:

– Processing: Jakob Grahn, Earth Observation Laboratory, University of Tromsø
– Includes material ©JAXA 2015, Included ©JAXA 2015, © PASCO, ©RESTEC
– RADARSAT-2 Data and Products © MacDonald, Dettwiler and Associated Ltd., 2015 – All rights reserved. Radarsat-2 data is provided by Norwegian Space Centre/Kongsberg Satellite Services under the Norwegian-Canadian Radarsat agreement 2015.

Image of the Week : 63 years of the Muir Glacier’s retreat

Image of the Week : 63 years of the Muir Glacier’s retreat

The Muir is a valley glacier (Alaska) that has significantly retreated over the last 2 centuries. The 3 pictures have the same field of view and record the changes that occurred during the 63 years separating 1941 and 2004.

In the 1941, the terminus of the glacier is on the lower right corner of the photo. The Muir is then a tidewater glacier up to 700m thick and is well connected to its tributary, the Riggs Glacier (upper right part of the photo).

9 years later, in 1950, the Muir Glacier has retreated by more than 3 km, is more than 100m thinner but is still connected to Riggs Glacier.

By 2004, the Muir glacier has retreated further inland and its terminus is no longer visible on the picture. The Riggs glacier is now disconnected to the Muir and has retreated by 0.25km. Vegetation has invaded the place.

Credits:

The photo comes from and the text is inspired from the section “Repeat photography of the Alaskan Glaciers” on U.S. Geological Survey website.
Photo 1: W. O. Field, # 41-64, courtesy of the National Snow and Ice Data Center and Glacier Bay National Park and Preserve Archive.
Photo 2 : W. O. Field, # F50-R29, courtesy of the Glacier Bay National Park and Preserve Archive.
Photo 3: B. F. Molnia, USGS Photograph

Image of the Week: Antarctic ice-shelf thickness

Image of the Week: Antarctic ice-shelf thickness

Thickness of floating ice shelves in Antarctica. Ice thickness is greatest close to the grounding line where it can reach 1000 meters or more (red). Away from the grounding line, the ice rapidly thins to reach a few hundreds of meters at the calving front. Ice thickness varies greatly from one ice shelf to another. Within ice shelves, “streams of ice” can be spotted originating from individual tributary glaciers and ice streams.

This dataset was used to compute calving fluxes and basal melt rates of Antarctic ice shelves (see Depoorter et al, 2013). This ice thickness map was derived from altimetry data (ERS and ICESat) acquired between 1994 and 2009 and corrected for elevation changes during this period.

Follow this link to download the georeferenced map and see Depoorter et al (2013)‘s paper for more information.

Image of the Week : SAFIRE team getting ready to drill in Greenland

Image of the Week : SAFIRE team getting ready to drill in Greenland

How do you get a hot water drill onto an ice sheet? The Subglacial Access and Fast Ice Research Experiment (SAFIRE) uses a hot water drill to directly access and observe the physical and geothermal properties where the ice meets rock or sediment at the glacier-bed interface. Here, SAFIRE principal investigator Bryn Hubbard and post-doc Sam Doyle help fly in the drill spool at the start of the Summer 2014 field campaign on Store Glacier, Western Greenland. Three boreholes were successfully drilled and instrumented with thermistors, tilt sensors through the ice column, and subglacial water pressure, electrical conductivity, and turbidity sensors at the ice-bed interface. Further work will be carried out in Summer 2016, when more instruments will be installed at the study site, and more helicopter slinging will be needed.

Image of the week : formation of an ice rise

Image of the week : formation of an ice rise

Deglaciation and formation of an ice rise with the ice-sheet model BISICLES.  The simulation starts with an ice sheet in steady state that overrides a topographic high in the bed, close to the calving front. The sea level is then forced to rise steadily with 1 cm per year during 15 thousand years, and the simulation goes on until the ice sheet reaches steady state.
The animation below shows that the formation of an ice rise delays the grounding line retreat.

For more information see Favier and Pattyn (2015)‘s recent paper.

movieicerise

The  movie shows the ice sheet retreat and the ice rise formation and evolution in between the two steady states. The movie starts after 5 thousands years of sea level rise. The ice upper surface is colored as a function of the velocity magnitude. The ice lower surface is colored either in light gray for floating ice or dark gray for grounded ice. Credit: L. Favier.