Author Archives: Andreas Muenchow

North Greenland Glacier Ice-Ocean Interactions 2014

I will travel to Spitsbergen in six weeks to board the German research icebreaker Polarstern. She will sail west across the Fram Strait towards northern Greenland where some of the last remaining glaciers exist that still discharge their ice via extensive floating ice-shelves. If all goes well, we will deploy instruments on the bottom of the ocean across a 30 km wide submarine canyon (Norske Ore Trough). The instruments profile ocean velocities from the bottom to the surface of the canyon that connects the deep (warm) ocean to the shallow continental shelf areas which then connect to two large outlet glaciers, Zachariae and 79N Glaciers. These are two of three glacier that terminate the North-East Greenland Ice Stream (NEGIS) which contains about 15 per cent of Greenland’s ice sheet:

Speed of Greenland's ice sheet movements. NE indicates the fast-moving (red) North-East Greenland Ice Stream with 3 branches connecting it to the ocean. [From Mauri Pelto's blog]

Speed of Greenland’s ice sheet movements. NE indicates the fast moving (red) North-East Greenland Ice Stream with 3 branches connecting it to the ocean. [From Mauri Pelto's blog]

The most southern is Storstrommen Glacier, a tidewater glacier with an almost vertical glacial front attached to the bedrock. The next one up north is Zachariae Glacier which lost its extensive ice-shelf during the last 3 years in a dramatic collapse reported on Mari Pelto’s blog. Presumably, there is little floating ice-shelf left that is attached to the lacier. And only 30 km to the north, we have 79N Glacier whose real name is the Danish Nioghalvfjerdsfjorden. It rivals Petermann Gletscher in ice discharge, areal coverage, thickness, and more with one exception: Nioghalvfjerdsfjorden’s ice-shelf appears remarkabe stable, nobody knows why exactly, but it may provide clues on how Greenland’s ice sheet interacts with and responds to forcing by the oceans. I show a recent Landsat image taken from Neven’s Arctic Sea Ice Forum; the floating glacier is on the left (east) of the image with a set of 5-7 out-cropping islands towards the right (west) providing some pinning support for the ~30 km wide front of the glacier:

Landsat image of Nioghalvfjerdsfjorden on Mar.-22, 2014.

Landsat image of Nioghalvfjerdsfjorden on Mar.-22, 2014.

Our 2014 study area is actually to the east, just outside the frame of the above image. The reason is lack of ship time, as this year’s deployment is just a small pilot study to better prepare and understand a larger German-led experiment that will take place both on the glacier and its adjacent ocean and land in 2016 and, I hope, beyond. Furthermore, we are scheduled to be there in June, a tad early for all the sea ice to clear out of the area (79N Glacier MODIS summer imagery) which also explains my intense interest in how the ice develops. And a first fairly clear MODIS image came about yesterday morning:

Ice-covered coastal waters off northeast Greenland April 14, 2014. Red contour indicates 100-m water depth. The "horseshoe" shaped red island is Belgica Bank with Norske Oer Trough to its south-west.

Ice-covered coastal waters off northeast Greenland April 14, 2014. Red contour indicates 100-m water depth. The “horseshoe-shaped red island is Belgica Bank with Norske Oer Trough to its south-west.

Belgica Bank is about as big as the Georges Bank in the Gulf of Maine. In past decades rafted multi-year ice and tabular icebergs often grounded over shallow Belgica Bank and thus provided an anchor to maintain stability for a year-round land-fast ice cover called the Norske Oer Ice Barrier. This year-round land-fast ice area, however, disintegrated in 2003 and has become an intermittent and not a regular feature for unknown reasons.

Before I can get onto the German icebreaker in Spitsbergen, my 3500 kg of equipment had to be repaired, rebuilt, re-powered, and shipped from British Columbia to Germany via rail, ocean freighter, and truck. It all arrived in 86 pieces only last friday, two weeks behind schedule, because of ice and confused shipping schedules in the Canadian Gulf of St. Lawrence. Lots of great people in Canada, the USA, and Germany made it happen. Wish us luck for the next step in this exciting scientific exploration to reveal one of many of Greenland’s glacier and ocean mysteries.

Hughes, N., Wilkinson, J., & Wadhams, P. (2011). Multi-satellite sensor analysis of fast-ice development in the Norske Øer Ice Barrier, northeast Greenland Annals of Glaciology, 52 (57), 151-160 DOI: 10.3189/172756411795931633

Wadhams, P., Wilkinson, J., & McPhail, S. (2006). A new view of the underside of Arctic sea ice Geophysical Research Letters, 33 (4) DOI: 10.1029/2005GL025131

Fram Strait Ice, Oil, and Glaciers

Tomorrow I fly to Germany to prepare for an ocean experiment in the shallow waters off northern Greenland. Together with oceanographers from the Alfred Wegener Institute (AWI), Germany, I hope to deploy 5 ocean current measuring devices on the bottom of the ocean for 2-3 years in Norske Oer Trough to the west of Belgica Bank inside the little black box to measure the ocean heat moving deep below the surface towards 79N Glacier, one of the last remaining glaciers of Greenland with an attached ice shelf floating atop the ocean:

Map of North Greenland with shallow (red/yellow) and deep (blue) oceans. Future study area are black boxes on the continental shelf of north-east Greenland.

Map of North Greenland with shallow (red/yellow) and deep (blue) oceans. Future study area are black boxes on the continental shelf of north-east Greenland. Small box is the area shown via MODIS imagery below.

Anotated MODIS images of 79N Glacier and Zachariae Icestream in September 2009 (left) and 2013 (right). Thick red line is 100-m depth with icebergs grounded on Belgica Bank often supporting extensive land-fast ice such as in 2009 but not 2013.

Anotated MODIS images of 79N Glacier and Zachariae Icestream in September 2009 (left) and 2013 (right). Thick red line is 100-m depth, thin red lines 200 and 300-m depth. Icebergs often ground on Belgica Bank (<100- deep) supporting extensive land-fast ice such as in 2009 but not 2013.

To do this, I need about 7000 pounds of equipment to get from western Canada to northern Greenland. All this stuff sits in the Port of Montreal (Canada) waiting for the freighter “Montreal Express” to ship it all to Hamburg and Bremerhaven to be loaded onto the R/V Polarstern, AWI’s research icebreaker. All ships are tracked via https://www.marinetraffic.com/en/ in real time and, I just checked, she just left Hamburg for Montreal this morning.

The Arctic research community is tiny and I try my darnest to share data, news, and developments without breaking confidences. A good friend and colleague of mine, Prof. Preben Gudmandsen, lives and works in Denmark. He is as excited as am I about all things related to Greenland which includes the upcoming experiment(s) in Fram Strait. By training Preben is an electrical engineer and helped developed some of the first radars with which to probe Greenland’s ice-sheet. We visit and e-mail each other as often as our professional and private lives allow, but he just sent me these images of western Fram Strait off Greenland:

And on related matters, I discovered earlier this week that Norway’s StatOil has a license to explore this very shelf area for oil and gas exploration as explained in this official StatOil press release that also includes this map

Norway's StatOil lease area on the continental shelf off north-east Greenland from their Dec.-20, 2013 press release.

Norways StatOil lease area on the continental shelf off north-east Greenland just to the south-east of Belgica Bank, taken from their Dec.-20, 2013 press release.

I also learnt that they sponsored mooring deployments in 2012/13 and 2013/14 with the Norwegian Polar Institute and the Norwegian University of Science and Technology in Trondheim. A 5-minute video of the cruise is posted at

There is much more to explore and think about here, but this will have to await a future blog when my mind is less cluttered by ship and travel schedules, paper and proposal writing, data and computer chasing, or just keeping a crazy life of working across 9 time zones together. Scientific life is good and fun, but exhausting and nerve-wrecking at times.

Budéus, G., & Schneider, W. (1995). On the hydrography of the Northeast Water Polynya Journal of Geophysical Research, 100 (C3) DOI: 10.1029/94JC02024

Hughes, N., Wilkinson, J., & Wadhams, P. (2011). Multi-satellite sensor analysis of fast-ice development in the Norske Øer Ice Barrier, northeast Greenland Annals of Glaciology, 52 (57), 151-160 DOI: 10.3189/172756411795931633

Wadhams, P., Wilkinson, J., & McPhail, S. (2006). A new view of the underside of Arctic sea ice Geophysical Research Letters, 33 (4) DOI: 10.1029/2005GL025131

Arctic Heart Beat and Disappearing Old Ice

Have a look at this beautiful movie that shows how the Arctic Ocean moves its oldest and thickest ice around from 1987 through 2013:


[Credits: Dr. Mark Tschudi, University of Colorado and NOAA's climate.gov.]

The Beaufort Gyre moves ice off western Canada and Alaska clockwise while the Fram Strait outflow between eastern Greenland and Spitsbergen exports much of the ice into the North Atlantic Ocean with the East Greenland Slope Current. The dividing line between the westward flux (into the Beaufort Gyre) and the eastward flux (into Fram Strait) stretch out to the north of the Canadian Archipelago and Greenland.

My only quibble is that, according to the movie, no old ice exits via Nares Strait or the Canadian Archipelago which is not true. During our field work in Nares Strait from 2003 through 2012 we always met rather heavy, thick, and old ice streaming south:

A graduate student in our oceanography program, Autumn Kidwell, is credited with directing me to this movie. Oh, and the Norwegian Ice Service in Tromso has a job opening for a smart remote sensing person ;-)

Norway, Norwegians, and Normal

The best part of my High School was getting out of it early to ski from Oslo to Trondheim across Norway’s Hardangervidda in 1981 Continue reading

Petermann Gletscher Thawing and Thinning

Greenland’s tidewater glaciers are losing mass, through thinning and retreat, at an increasing rate. Greenland’s glaciers located north of 78 North latitude often end in ice shelves, floating extensions of the glaciers extending up to several tens of km into the adjacent fjords. While most ice shelves of North Greenland have been relatively stable, Petermann Gletscher lost more than 40% of its ice shelf area (36 giga tons) during two major calving events in 2010 and 2012. What remains of Greenland’s ice shelves is threatened by a changing climate, because both regional air and ocean temperatures continue to increase while Arctic sea ice cover continues to decline.

Petermann Gletscher through calving events. White lines show ICESat tracks; red (ambient ice shelf) and blue (central channel) show repeat-track airborne surveys.

Petermann Gletscher through calving events. White lines show ICESat tracks; blue (ambient ice shelf) and red (central channel) show repeat-track airborne surveys.

Using lasers and ice sounding radars aboard NASA planes (Operation IceBridge) as well as lasers on a now defunct satellite (ICESat), oceanographer Laurie Padman, glaciologist Helen A. Fricker, and I just passed peer-review with a study that estimates how much Petermann Gletscher has shrunk and melted over the last decade or so. The quick answer is about 5 meters per year:

(top) Change in ice thickness from 2007 to 2010 from repeat airborne missions. (middle) along-track mean thickness. (bottom) steady-state melt.

(top) Change in ice thickness from 2007 to 2010 from repeat airborne missions. (middle) along-track mean thickness. (bottom) steady-state melt.

In our study we distinguished between 1. a thinning of the floating ice shelf that moves along the glacier as new ice moves from the Greenland ice sheet on land out into the ocean and 2. a non-steady thinning at fixed locations as time passes. The situation is somewhat similar to the flow through a pipe (or river, if you wish) with a constriction. If the same amount of water entering the pipe comes out at the other end, then the flow has to speed up where the pipe becomes narrow. A floating glacier is not quite like water flowing through a pipe, because the ocean underneath and the air above can melt ice making the floating ice shelf thinner as it flows along. If the ice thickness changes along the floating glacier, then melting must take place for a glacier moving seaward at a constant rate. The ice thickness changes along the glacier, but stays constant at a fixed location. This is the steady-state melt.

The non-steady state thinning is the change in ice thickness at a fixed point observed at different times. We estimated this from observations taken along exactly the same tracks that the NASA aircraft flew in 2007 and 2010 before the break-up of Petermann Gletscher. Prior studies could not measure this, because the tracks were not the same or because the signal processing was not up to the task. We find that both the steady and the non-steady contribution is about 5 m per year each. These rates do not vary much between a thin central channel or a thick ambient ice shelf. This came as a little bit of a surprise, because the central channel is often also refered to as a “melt channel,” but it actually melts no different from any other section of the ice shelf. So, the question remains as to what causes the central and many other channels to be there in the first place. The place to look, I feel, is the area where the bed rock, the glacier ice, and the Arctic Ocean meet in what is called the grounding zone. It is here that the gigantic forces of water and ice pulverize rock while a mixture of rock and pressurized water is sand-blasting the ice. Talking about a rock and a hard place …

Our study will appear later this year in the Journal of Glaciology, but pre-prints can be downloaded here. The U.S. tax-paying public funded this study via grants that we received from NASA and NSF. They also funded substantial efforts to make sure, that all data reside in the public domain accessible to anyone anywhere.

Münchow, A., Padman, L., and Fricker, H.A. (2014). Interannual changes of the floating ice shelf of Petermann Gletscher, North Greenland from 2000 to 2012, Journal of Glaciology, in press

Johnson, H., Münchow, A., Falkner, K., & Melling, H. (2011). Ocean circulation and properties in Petermann Fjord, Greenland Journal of Geophysical Research, 116 (C1) DOI: 10.1029/2010JC006519

Rignot, E., & Steffen, K. (2008). Channelized bottom melting and stability of floating ice shelves Geophysical Research Letters, 35 (2) DOI: 10.1029/2007GL031765