Category Archives: Polarstern

Coastal Oceanography off North-East Greenland

Greenland is melting, but it is not entire clear why. Yes, air temperatures continue to increase, but what does it matter, if those temperatures are below freezing most of the time. What if the ocean does most of the melting a few 100 m below the surface rather than the air above? It means that gut feeling and everyday experience can be poor guides for science, it means that there is more than meets the eye, and it means that some of Greenland’s melting happens out of sight without the dramatic imagery of a rapidly disintegrating glacier that sends icebergs out to sea.

Floating section of 79N Glacier in north-east Greenland as seen from LandSat in march 2014.

Floating section of 79N Glacier in north-east Greenland as seen from LandSat in march 2014.

In order to “see” where changes may happen out of sight American tax payers supported me via the National Science Foundation (NSF) to use available University of Delaware ocean sensors from an available German ship to investigate the ocean near two large glaciers off north-east Greenland. The sensors are in the water for over a year now and will stay there for another to collect data every half hour. The data are stored on computers inside the sensors and it is a marvel of smart engineering that we can measure water temperature, salinity, and velocity at the bottom of an ice-covered ocean. Now what would I do with such data?

Two ocean sensor packages ready for deployment near Isle de France, Greenland 10 June 2014.

Two ocean sensor packages ready for deployment near Isle de France, Greenland 10 June 2014.

First, one needs to know that in the Arctic Ocean temperature increases as one moves a thermometer from the surface towards the bottom for the first 900 feet or 300 meters. This only make sense, if the warm water is heavier than the cold water above. This is the case in the Arctic, because the warm water at depth is also very salty. The cold waters above contain less salt and that’s why they float. The warmest waters originate from the Atlantic Ocean to the south-east of Iceland. Lets call it Atlantic Water for this reason. The surface waters contain sea ice and its fresh melt water and thus are always close to the freezing point, so lets call them Polar Waters.

Vertical profiles of temperature and salinity across Norske Ore Trough, Greenland. The insert shows station locations for profiles (small symbols) and moorings (large circles). The red dot marks the location of the red profile.

Vertical profiles of temperature and salinity across Norske Ore Trough, Greenland. The insert shows station locations for profiles (small symbols) and moorings (large circles). The red dot marks the location of the red profile.

All along the East Coast of Greenland, we find a strong southward flow of ice and Polar Water called the East Greenland Current. On a rare clear day one can “see” this flow as a beautifully structured undulating band separating the deep Greenland Sea from the shallow and broad continental shelves. Now recall that the warmest waters are in the Atlantic layer way down and somewhat offshore. How do these waters cross the East Greenland current and the very wide continental shelf to reach the glaciers along the coast? It is this question my project tries to answer with lots of help from NSF and German friends.

Satellite image ocean current instabilities on Aug.-19, 2014 as traced by ice along the the shelf break, red lines show 500, 750, and 1000 meter water depth. Small blue triangles top left are ocean moorings.

Satellite image ocean current instabilities on Aug.-19, 2014 as traced by ice along the the shelf break, red lines show 500, 750, and 1000 meter water depth. Small blue triangles top left are ocean moorings.

We think that the warm and salty waters flow near the bottom below the East Greenland Current at deep bottom depressions such as canyons. Testing this idea, we placed our sensors in a line across the canyon with a small ice-capped island called the Isle of France on one side and Belgica Bank on the other. We deployed seven instrument as an array across the canyon to measure the speed and direction of the flow as well as its temperatures and salinities. Our canyon connects the deep Greenland Sea 150 miles to the east with two glaciers another 100 miles to the north-west. We all anxiously hope that no iceberg wiped out bottom moorings and that they all record data faithfully until the summer of 2016 when we plan to recover instruments and data.

Section of temperature across Norske Ore Trough with Isle de France, Greenland on the left and Belgica Bank towards Fram Strait on the right. The view is towards 79N Glacier.

Section of temperature across Norske Ore Trough with Isle de France, Greenland on the left and Belgica Bank towards Fram Strait on the right. The view is towards 79N Glacier.

Before and after the placement of our moored instruments, however, we did survey the section from the ship and I show the temperature and salinity across our canyon. We now see that the water below 200 m depth are indeed very warm and salty as expected, but there is a detail that I cannot yet explain: notice the slight upward sloping contours of salinity near km-80 at the rim of the canyon and the downward sloping contours on the other side near km-10. Such sloping contours represent a flow out of the page at km-80 and into the page at km-10 which is exactly the opposite of what I expected. All I can say at the moment is that this snapshot does not resolve motions caused by the tides, the winds, and the seasonal cycles properly, but our moorings do. So, there are still mysteries to be solved by the data sitting on the bottom of the ocean guarded by towering spectacles of ice.

Tabular iceberg and sea ice cover near Isle de France 10 June 2014

Tabular iceberg and sea ice cover near Isle de France 10 June 2014

[This entry will be submitted to NSF as a Final Outcome Report for award 1362109 “Shelf-Basin Exchange near 79N Glacier and Zachariae Isstrom, North-East Greenland.” The work would not have been possible without the generous support of NSF as well as the German Government as represented by the Alfred Wegener Institute who sponsored the expedition to North-East Greenland in 2014. Torsten Kanzow, Benjamin Rabe, and Ursula Schauer of AWI all deserve as much and even more credit for this work than do I.]

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

Reeh, N., Thomsen, H., Higgins, A., & Weidick, A. (2001). Sea ice and the stability of north and northeast Greenland floating glaciers Annals of Glaciology, 33 (1), 474-480 DOI: 10.3189/172756401781818554

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

American Adventures Abroad: The Four Germanies

I am American and damn proud of it. I was born in Germany, left almost 30 years ago, and, like a plant from another ecosystem, I am exposed to the new Germany for the first time. I know the difficult histories of both West and East Germany that since 1989 are one united country. The 100 people aboard the research icebreaker R/V Polarstern perhaps represent this new country well. Most crew and scientists were born and raised in either East or West Germany, extinct countries which each had a range of characters to form a distinct and diverse German fabric:

The first person I met when boarding the ship in dry dock was X. After introducing myself as an American scientist to sail the FS Polarstern in stilted if decent German, he revealed to me that he volunteered in the NVA, the soviet-style Nationale Volks-Armee for more than 10 years. Like many low-level Nazis a generation or two before him, he argues that not all was bad in the regime that he served. While this may be true, it strikes me odd, that this is the first things one reveals of oneself and a regime that created walls and killing zones to prevent its own citizens from leaving. Suspecting an uneasy history of guilt, I did not argue despite strong feelings to present different perspectives. Hence his next move is to state that American activities in Europe, Asia, South-America, Middle East, and Africa are the root source of all the problems in these regions. Again, not taking the bait, I listen, ask gentle probing questions to expose more detail, however, not much follows after the first rant that, perhaps, reflects a general feeling more than fact. I heart variations of this theme often in Germany both at sea and on land.

Our nurse and stewardess Kerstin also hails from the former East-Germany where she grew up the same time that I did in West-Germany, but unlike X., she embraces life as it presents itself without resentment, regret, or judgment. She signed on for a year working aboard Polarstern for a sense of adventure and to see the world in a different way. She is naturally curious on all things that relate to people, science, and life. She has little interest in politics, ideologies, and theories on how the world works, but she uses her own mind, experiences, and stories to make everyone around her laugh often. People like her should run the world.

The second Mate, Felix, was in charge when I boarded the ship. He is probably in his early 30ies and gave me the first tour of the ship in dry dock, a task that revealed a deep pride in the ship, its capabilities, and all it represents in a forward-looking modern Germany. He has clearly sailed to many ports and dealt successfully with people of different countries, cultures, and educations. Despite cursing and cussing of an ol’ salt, he is a hard-working, no-nonsense guy who gets things done efficiently. He also smokes like a chimney and likes to drive the ship while breaking sea ice. He did this often and smartly throughout the expedition.

A wonderful surprise to me aboard this ship is the large number of foreigners. There are three Danes aboard one of whom hails from New Zealand; two Canadians, two Belgians, and two Englishmen are aboard; while Brazil, China, Netherlands, Poland and the USA are each represented by one scientist. The two Canadians may as well come from two different countries, as one hails from English-speaking British Columbia and the other from French-speaking Montreal. Catherine’s Quebecoise language and perspectives are the most beautiful of all on this diverse ship. I could listen to her for hours …

Then there is a fourth group aboard who are perhaps the largest: They are the very young Germans who were born after the collapse of the communist empires in the East and they will become the new Germany. It is a foreign country to me, one I like from the distance, and it is a very young country with much potential to make a positive impact in the world.

Science party aboard R/V Polarstern after 4 weeks at sea in July 2014.

Science party aboard R/V Polarstern after 4 weeks at sea in July 2014.

Arctic Oceanographers Ashore In Tromso

Oceanographers are a bit crazy. This is especially true after sailing and working 4 weeks aboard a ship in the ice and fog and snow and drizzle that characterize summer in Fram Strait between northern Greenland and Spitsbergen. The one color one does NOT see is green, there just is none. So, when we got off FS Polarstern last thursday, what did we do? Continue reading

Of Moorings, Elephants, Norwegians, and Codswallop

The oceans are cruel, unforgiving, and destructive. Microbes, algae, plankton, fish, and whales all evolved slowly to make the seas their home. We men and women of science and technology race to catch-up Continue reading

Deep Sea Biology and Chemistry: Muddy Business

Mud, mud, and more muddy mud was hauled from the bottom of the ocean for
the last five days from depths of one, two, and even three miles below the
icy surface. The biologists aboard are having a Continue reading