CR
Cryospheric Sciences

Cryospheric Sciences

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: Ice Sheets in the Climate

Image of the Week: Ice Sheets in the Climate

Ice sheets play a central role in the climate system. They store significant amounts of fresh water and are the conveyor belts for transporting snow that accumulates on land back into the oceans. The figure above shows a few of the ice-climate interactions. In the figure below (click on the figure for full resolution) we see the complete picture of the processes taking place between ice sheets, solid earth and the climate system. These interactions have an internal variability but also affect the coupled ice sheet–climate response to external forcings on time scales of months to millions of years. The inlay figure represents a typical height profile of atmospheric temperature and moisture in the troposphere.

If the current warming of the climate continues, the ice sheets will respond at a yet unknown rate, with unknown consequences for the rest of the climate system. Decisions reached at COP21 in Paris this week  may impact the future of our ice sheets and halt the current trend.

FigBox5.2-1_interaction_ice_sheet_rest

The interaction of ice sheets with the climate system. Credit: Figure 1 in Box 5.2, IPCC AR5.

Image of the Week: Atmospheric CO2 from ice cores

Image of the Week: Atmospheric CO2 from ice cores

The measurements of atmospheric CO2 levels at Manu Loa, Hawaii read 401.01ppm on the 7th of December this year. To understand the significance of this number, you just need to look at the figure above from the 4th IPCC report. It shows the changes in CO2 concentrations during the past 800,000 years based on ice core measurements. Values have fluctuated between 190ppm and 280ppm. In other words, both the level of present-day atmospheric CO2 and the rapidity of the increase is unprecedented.

The figure also shows the projections from the IPCC AR4 report for different emission scenarios. Which scenario will turn out to be the most likely might be determined at COP21 in Paris right now.

Read more:

Measurements at Manu Loa, Hawaii

Image of the Week: Changes in Snow Cover

Image of the Week: Changes in Snow Cover

Who is dreaming of a white spring?

In daily life we might be more interested in the chances of a white Christmas, but the amount of snow-covered ground in the spring is a very good indicator of climate change. The figure above shows the projected change in snow cover extent in the Northern hemisphere in March-April according to different future scenarios (i.e. Representative Concentration Pathways or RCPs of the IPCC). All the scenarios predict a decrease in spring snow, and the reduction goes up to 30% by 2100, for the most pessimistic scenario.

Below is shown the changes in snow cover in historical times for the Northern hemisphere, the grey line is the change in snow cover in the spring. The red crosses are based on satellite data and show the snow cover in June. Undoubtedly, we are heading for a warmer climate but it would also seem that springtime skiing holidays could become a thing of the past.

The COP21 meeting will determine what steps will be taken in the future and which scenario path we will follow. Regardless of whether you worry about the future of our planet or the future of your skiing holiday – you should take an interest.

March–April NH snow cover extent (SCE, circles) over the period of available data, filtered with a 13-term smoother and with shading indicating the 95% confidence interval; and June SCE (red crosses, from satellite data alone), also filtered with a 13-term smoother. The width of the smoothed 95% confidence interval is influ- enced by the interannual variability in SCE. Updated from Brown and Robinson (2011). For both time series the anomalies are calculated relative to the 1971–2000 mean.

March–April NH snow cover extent (circles) over the period of available data, filtered with a 13-term smoother and with shading indicating the 95% confidence interval; and June (red crosses, from satellite data alone), also filtered with a 13-term smoother. The width of the smoothed 95% confidence interval is influenced by the interannual variability in SCE. For both time series the anomalies are calculated relative to the 1971–2000 mean.

 

The figures in this blog post are taken from the IPCC report (Fig. TS-18 and Fig. 4.19 respectively). You can read more here:

Vaughan, D.G., J.C. Comiso, I. Allison, J. Carrasco, G. Kaser, R. Kwok, P. Mote, T. Murray, F. Paul, J. Ren, E. Rignot, O. Solomina, K. Steffen and T. Zhang, 2013: Observations: Cryosphere. 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 [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

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.

Sunshine, ice cores, buckets and ALE: Antarctic Fieldwork

Sunshine, ice cores, buckets and ALE: Antarctic Fieldwork

My Antarctic adventure started from Punta Arenas at the bottom of Chile, opposite Tierra del Fuego, on New Years Eve 2014 after a long journey from Heathrow via São Paulo and Santiago.

Punta Arenas

Punta Arenas is even quieter than usual on New Year's Day. (Credit: M. Millman)

Punta Arenas is even quieter than usual on New Year’s Day. (Credit: M. Millman)

Punta Arenas is where Shackleton organised the rescue of his men from Elephant Island after his voyage to South Georgia in the James Caird. It is also where I met my PhD supervisors Chris Fogwill and Chris Turney for the first time, along with ancient-DNA expert Alan Cooper. Punta is the base for Antarctic Logistics & Expeditions (ALE), who are part funding my PhD and supporting me and my supervisors in the field.

Off to Antarctica…

Arriving at Union Glacier on the Ilyushin. (Credit: H. Millman)

Arriving at Union Glacier on the Ilyushin. (Credit: H. Millman)

After a couple of days in Punta Arenas, when the weather was right, we boarded an Ilyushin and flew the 4.5 hours to ALE’s base at Union Glacier in the Ellsworth Mountains. The Ilyushin is a big, rough-and-ready Russian transport plane equipped with an emergency rope instead of inflatable slides. We sat in the front half of the cabin and the back was packed with fuel and supplies for the base.

Union Glacier is a hub for an assortment of mountaineers, explorers, tourists and scientists. By Antarctic standards the base is very luxurious, with toilet blocks and even showers. Our bags were taken from the Ilyushin and were waiting for us outside our clamshell tent: “Scott”. All the tents are named after polar explorers and they have proper camp beds and solid floors inside. With regular Ilyushin flights, there is plenty of fresh food and the chefs cook fabulous breakfasts, lunches and suppers. The mix of people coming and going means that there are plenty of interesting stories to hear at mealtimes.

Union Glacier base. (Credit: H. Millman)

Union Glacier base. (Credit: H. Millman)

There was an American military man who had parachuted out of an Ilyushin to the North Pole, a cancer survivor who was trekking to the pole to raise millions of pounds for Cancer Research and lots of people who had climbed six of the seven summits and were in Antarctica to climb Mt Vinson, the last of the seven.

The fieldwork

Map showing the Patriot Hills and Union Glacier. It took about 20 minutes for the Twin Otter to reach the Patriot Hills from Union Glacier base. (Credit: H. Millman)

Map showing the Patriot Hills and Union Glacier. It took about 20 minutes for the Twin Otter to reach the Patriot Hills from Union Glacier base. (Credit: H. Millman)

Good weather meant that we couldn’t enjoy Union Glacier for long and soon the Twin Otter was loaded with all our equipment and the four of us were flown out to our field site: the Patriot Hills in the Horseshoe Valley.

The deep blue colour of the ice is visible looking down the core hole. (Credit: H. Millman)

The deep blue colour of the ice is visible looking down the core hole. (Credit: H. Millman)

The Horseshoe Valley is at the end of the Heritage Range, close to the grounding line in the Weddell Sea. Katabatic winds blowing down the side of the Patriot Hills have caused a blue ice area to form. The chance to sample the old ice, which comes to the surface in these areas, is what brought us to Antarctica. Over the next few weeks we drilled a snow/firn core, and ice cores in the blue ice area. Surface samples were collected by Professor Chris Turney, crawling 1.6 km on his knees as though trying to appease the God of the Glacier, with a cordless drill from a DIY store.

Once we get back to the lab, the samples will be analysed for trace gases, isotopes, tephra and ancient DNA. From this data we are hoping to extract a climate record reaching back to the Last Interglacial (~135 – 116 ka). I will then use this record, along with other proxy records and GCM outputs, to drive the PISM-PIK ice sheet model. This will help to answer the main question of my PhD, which is: What was the Antarctic contribution to sea level rise during the Last Interglacial? Global average temperatures during the Last Interglacial were 1-2°C warmer than pre-industrial times. As we move into a similar climate today, the past can be used as a process analogue for what might happen in the coming decades.

Drilling using a Kovacs corer. Here I'm wearing 3 coats: a light down jacket, a soft windproof shell, and my big down jacket on the top. I'm also wearing down trousers over my salopettes. It's quite windy on the blue ice, so it can feel very cold. (Credit: H. Millman)

Drilling using a Kovacs corer. Here I’m wearing 3 coats: a light down jacket, a soft windproof shell, and my big down jacket on the top. I’m also wearing down trousers over my salopettes. It’s quite windy on the blue ice, so it can feel very cold. (Credit: H. Millman)

A digression on “everyday” life in Antarctica…

Our small camp in the Horseshoe Valley. (Credit: H. Millman)

Our small camp in the Horseshoe Valley. (Credit: H. Millman)

We set up our camp a little way away from the blue ice to avoid the worst of the katabatic winds. Camp consisted of a big mess tent and 3 sleeping tents. Fogwill and me had our own tents, but Turney and Cooper had to share. Turney and Cooper were struck down with colds and we took extra care to disinfect or quarantine anything the infected had touched because having a cold in Antarctica is a thoroughly miserable experience. Fortunately, we had lots of hot, hearty meals because ALE had sent us off with excellent frozen meals cooked by their chefs. We had curries, lasagna, stews, bread rolls and cake, and we only had to eat de-hy for lunch. The only food I missed was raw carrots.

Women - Pee here! (Credit: H. Millman)

Women – Pee here! (Credit: H. Millman)

For obvious reasons, snow for drinking water was collected up-glacier of the camp, and the latrine was located down-glacier. We took it in turns to collect and melt snow for drinking water. Our toilet tent had about 3 or 4 different incarnations as storms buried our previous efforts. By the end, we found the best design was dug down about 1 m, with snow blocks and fuel barrels around it supporting a wooden board and a sheet of tarpaulin. This stopped snow getting in during a storm, but the tarpaulin could also be wrapped around your neck so that one’s body could appreciate the warmth rising up from the latrine, while keeping one’s nose out in the fresh air. All waste is collected in containers so that it can be flown out to Chile on the next Ilyushin- all human waste has to be removed from Antarctica. Since the men have the advantage of being able to wee straight into the pee barrel, ALE kindly supplied me with my very own wee bucket, which I was extremely grateful for, particularly after an unpleasant incident with a SheWee at 3am, during a storm.

The good weather meant that we were able to work most days. We had a couple of stormy days which allowed us to rest, read, listen to music, tidy down the camp, and recharge our batteries (literally). Electrical things aren’t at their happiest in the Antarctic cold. My iPod wiped itself in the last week and we had to hug our laptops inside our jackets to keep them warm enough to hold some charge.

…back to reality

Once we’d collected all of our samples, it was time to leave the Patriot Hills and return to Union Glacier. We started packing things away while we were waiting for the Iridium call from the base, not knowing whether the Twin Otter would arrive that afternoon or tomorrow or the day after, or the day after that. We got the call and the Twin Otter was already on its way. A mad rush followed as we had to quickly but carefully dig out all of our tents from weeks’ worth of icy snow and pack them away. The plane landed less than 30 minutes later with the ALE guides who were going to take our skidoos back. With their help, we soon had everything loaded onto the plane, with just enough room for the four of us to squeeze in like sardines.

Quickly packing up our camp because the Twin Otter has just arrived to take us back to Union Glacier base. (Credit: H. Millman)

Quickly packing up our camp because the Twin Otter has just arrived to take us back to Union Glacier base. (Credit: H. Millman)

Returning to the civilisation of Union Glacier was very exciting, especially seeing other people for the first time. I’m usually quite a shy and quiet person, but all reserve vanished in my first hours back on the base as I enthusiastically bounded up to strangers and asked to hear their life stories. The first wash was also fantastic. My hair had been a solid greasy mass of nastiness for weeks and having it back to its fluffy state was a joy. While we waited for a weather window so that the Ilyushin could come and collect us, we sub-sampled our snow/firm core, mended our tents and organised which equipment would be staying in Antarctica and what we’d be taking back. While we were doing this, ALE were starting to pack away Union Glacier base for the winter.

We flew back to Punta on the penultimate Ilyushin of the season, so most of the other passengers were the staff. Everyone was sad to leave, but looking forward to seeing family and friends at home after months away. On returning from Antarctica, even the quiet town of Punta was an assault on the senses. The only smells in Antarctica are cooking, skidoo fumes and the latrine, so when we arrived back the smell of soil and vegetation seemed really strong. It took a few days to readjust to cars, dark nights, proper beds, baths, flushing toilets, running water, central heating, mobile signal, internet, televisions and unlimited electricity. Leaving civilisation was easier than returning to it.

Ice cores waiting for check-in at Punta Arenas airport. We wouldn't see them again until we landed in Sydney. (Credit: H. Millman)

Ice cores waiting for check-in at Punta Arenas airport. We wouldn’t see them again until we landed in Sydney. (Credit: H. Millman)

Our ice cores were stored in a refrigerated lorry back until our flight to Sydney via Santiago and Auckland. Although the cores were in special insulated boxes, the long flight with connections to the heat of a Sydney summer was very stressful. The previous season a box had been left behind at Auckland airport, resulting in a very expensive puddle. This year we were lucky and all boxes arrived at the other end and the unscathed cores were transferred to the freezers at UNSW. Now the hard work begins!

Chris Turney at the end of the 1.6 km transect. (Credit: H. Millman)

Chris Turney at the end of the 1.6 km transect. (Credit: H. Millman)

More information:

Project website: http://ellsworthmountains.com/index.html

Short videos from the field can be viewed on Chris Turney’s Vine page:
https://vine.co/u/1021019438360739840

Edited by Sophie Berger and Nanna Karlsson


About Helen Millman: 
After completing a BSc in Geography at Swansea University and a Glaciology MSc at Aberystwyth University, Helen moved from her native Devon in south-west England to Australia to start her PhD at the University of New South Wales in Sydney. Her research focuses on modelling Antarctic ice sheet dynamics during the Last Interglacial using data from ice cores, as well as outputs from the CSIRO Mk3L GCM to drive the Potsdam Parallel Ice Sheet Model (PISM-PIK). She is supervised by Chris Fogwill and Chris Turney at UNSW, Steven Phipps at the University of Tasmania and Nick Golledge at Victoria University in Wellington. You can follow Helen on Twitter @helenmillman (https://twitter.com/helenmillman).

Image of the Week: Greenland Glacier Seen from a Drone

Image of the Week: Greenland Glacier Seen from a Drone

The use of drones or Unmanned Aerial Vehicles (UAVs) is one of the most exciting development in glaciology in recent years. The picture was taken during fieldwork conducted in the summer of 2014 by Johnny Ryan and colleague Nick Toberg. The aim was to survey Store Glacier once a day using a fixed-wing UAV, that was equipped with a digital camera, which took photos every two seconds during its dangerous 40 km sortie over the glacier.

The project was a joint project between Aberystwyth University and the University of Cambridge, and the data provided insights into the process of calving and the interplay between the glacier and sea-ice mélange that forms during the winter and breaks up in late spring.

Read Johnny’s exciting blog post about the whole field season here.

Results from the study has been published in the The Cryosphere earlier this year.