Tag Archives: Greenland

Glaciers, Geocaching, and Greenland Goals

I thought it silly when my wife suggested to go geocaching with her. She told me it was to hunt for treasures and as a professor of physical ocean science and engineering this was not for me. But my wife is persistent, I am curious, and when she explained that a GPS, hiking, and computer mapping was involved, I gave it a try and have been hooked ever since. My first geocaching hiking trip took place on Anacortes Island, Washington in 2013 where our youngest son then lived. Here we are walking past rock carved 10,000 years ago by a tiny glacier at N 48° 29.498 W 122° 41.799 N that discharged ice into Puget Sound:

Glacier carved outcrop in Washington Park, Anacortes Island, WA.

Glacier carved outcrop in Washington Park, Anacortes Island, WA.

Since this first geocaching trip, I have found more than 200 geocaches in places small and remote and places large and urban. The treasure is in the walking and trying to find a path towards a destination, but the destination is secondary as many discoveries are made along the way.

This often happens in science also. One needs to know a destination, have a goal, formulate a hypothesis, but much science, learning, and discovering happens along the path towards that goal. With a GPS the destination is easy, it is a fixed point on earth, but it is harder in science. It can be useful to roam widely, but a set of intermediate goals can help to stay focused. For example, I want to understand how Greenland will change as we warm the earth. That’s a big question with impacts on floods in Europe, storms in the Americas, and rising sea level everywhere. This is a 100-year problem that many people work on; so my personal goal is to focus on how the oceans melt glaciers from below. This is a 10-year problem. It is a step towards the larger goal, but 10 years is still long even though I work with people in Germany, Canada, Denmark, England, Sweden, and Norway:

View to the south on the climb down from Tromsdalstinen.

View to the south on the decent from Tromsdalstinen on a geocaching trip in 2014 out of Tromso, Norway.

The photo above was made during one of my geocaching trip in northern Norway. Three physical oceanographers had gotten off the ship after they deployed ocean current measuring devices off eastern Greenland near a larger ice sheet. The experiment was designed to measure the ocean heat and its movement towards two large outlet glaciers. One has a wide and stable floating ice shelf, Nioghalvfjerdsfjorden (79N Glacier) while Zachariae Isstrom a few miles south lost its wide, long, and apparently unstable ice shelf that still shows in this 2002 image:

North-east Greenland: 79N Glacier and Zachariae Isstrom in 2002.

North-East Greenland in 2002 when both 79N Glacier (near 79 30′) and Zachariae Isstrom (near 79 00′) had extensive ice shelves (black areas are open ocean).

It puzzles me how two adjacent glaciers can and do behave so differently. If we understand how Greenland is melting, then we should explain the difference convincingly, but I am still looking for people who can. Lots of theories, lots of ideas, and lots of modeling, but there are not many observations to make the skimpy and often contradictory evidence convincing. And this finally leads me to my last point and the goal that I set for myself for the next 5-10 years:

I like to measure the ocean, the ice, and the air above and below floating glaciers via a small network of sensors. Now that two large ice islands spawned at Petermann Gletscher in 2010 and 2012, I believe that the remaining ice shelf will stay largely put for the next few years, that is, move at 1 km per year towards Nares Strait:

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; red (ambient ice shelf) and blue (central channel) show repeat-track airborne surveys.

The hardest part in reaching this goal is to get measurements from under the 200-600 meter thick ice. This requires holes drilled through the glacier, it requires ocean sensors to be lowered into the water below the glacier, and it requires connections to relay data back to the surface at all hours for many year. I  perhaps have a first chance towards this goal when the Swedish icebreaker Oden will work for a month in Petermann Fjord this year. People from the British Antarctic Survey will be aboard and they plan to drill holes for other scientific purposes. When they are done, the holes freeze over, unless someone (me, me, me, please, pretty, pretty please) has instruments to put in there. I just word that I will be aboard the ship as well and I am feverishly working towards this goal with much help from others. More on this in later posts. All science is a group effort.

I close with a photo to show how the ice-covered ocean of Petermann Gletscher looks during the polar day. Would it not be great to know the temperature of the water below and the air above this more than 200 meter thick glacier ice at all times posted for everyone to use with an internet connection?

March-24, 2010 view of Petermann Glacier from NASA's DC-8 aircraft. Photo credit goes to Michael Studinger of NASA's IceBridge program.

March-24, 2010 view of Petermann Glacier from NASA’s DC-8 aircraft. Photo credit goes to Michael Studinger of NASA’s IceBridge program.

East Greenland Current Instabilities

The coast off north-east Greenland is a grey, cloudy, and icy place. I spent 4 weeks on a ship earlier this summer to place sensors on the ocean floor to measure water currents, salinity, and temperature. The data shall uncover the mystery of how ocean heat 300 m below the surface gets to glaciers to melt them from below year round. My contribution is a small part of a larger effort by German, Norwegian, Danish, American, and British scientists to reveal how oceans change glaciers and how oceans impact Greenland’s ice sheet, climate, and weather.

So, for months now I am watching rather closely how this ocean looks from space. Usually it is cloudy with little exciting to see, but for 4 days this week the clouds broke and displayed a violently turbulent ocean worthy of a Van Gogh painting:

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

Satellite image of 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.

A wavy band of white near the red lines indicates the East Greenland Current. The red lines show where the water is 500, 750, and 1000 m deep. All waters to the left (west) of the red lines are shallow continental shelf while all waters to the right (east) are deep basin. Some islands and headlands of Greenland appear on the left of the image as solid grey. The image covers a distance about the same as from Boston to Washington, DC or London to Aberdeen, Scotland. Black areas are ocean that is clear of ice while the many shades of white and gray are millions of ice floes that act as particles moved about by the surface flow. Using a different satellite with much higher resolution shows these particles. The detail is from a tiny area to the north-west of the red circle near 77.5 North latitude:

Individual ice particles as seen on the north-east Greenland shelf from LandSat 15-m resolution from Aug.-21, 2014 near 77.5N and 10 W.

Individual ice particles as seen on the north-east Greenland shelf from LandSat 15-m resolution from Aug.-21, 2014 near 77.5N and 10 W.

Strongly white areas indicate convergent ocean surface currents that concentrate the loose ice while divergent ocean currents spread the ice particles out in filaments and swirls and eddies.

This is how many real fluids look like if one takes a snapshot as satellites do. Stringing such snapshots together, I show the fluid motion as comes to life for about 3 days:

Output

Notice how the large crests seaward of the red line between 74 and 75 North latitude grow and appear to break backward. This is an instability of the underlying East Greenland Current. It starts out as a small horizontal “wave,” but unlike the waves we watch at the beach, the amplitude of this “wave” is horizontal (east-west) and not vertical (up-down). The mathematics are identical, however, and this is the reason that I call this a wave. As the wave grows, it become steeper, and as it becomes too steep, it breaks and as it breaks, it forms eddies. These eddies then persist in the ocean for many weeks or months as rotating, swirling features that carry the Arctic waters of the East Greenland Current far afield towards the east. The East Greenland Current, however, continues southward towards the southern tip of Greenland. The wave and eddy processes observed here, however, weaken the current as some of its energy is carried away with the eddies.

I could not find any imagery like this in the scientific literature for this region, but similar features have been observed in similar ocean current systems that transport icy cold waters along a shelf break. The Labrador Current off eastern Canada shows similar instabilities as does the East Kamchatka Current off Russia in its Pacific Far East. And that’s the beauty of physics … they organize nature for us in ways that are both simple and elegant, yet all this beauty and elegance gives us complex patterns that are impossible to predict in detail.

Beszczynska-Möller, A., Woodgate, R., Lee, C., Melling, H., & Karcher, M. (2011). A Synthesis of Exchanges Through the Main Oceanic Gateways to the Arctic Ocean Oceanography, 24 (3), 82-99 DOI: 10.5670/oceanog.2011.59

LeBlond, P. (1982). Satellite observations of labrador current undulations Atmosphere-Ocean, 20 (2), 129-142 DOI: 10.1080/07055900.1982.9649135

Solomon, H., & Ahlnäs, K. (1978). Eddies in the Kamchatka Current Deep Sea Research, 25 (4), 403-410 DOI: 10.1016/0146-6291(78)90566-0

Men and Women on the Edge 1

EDIT: Original post was too long and rambling. One advice by wise female council, I decided to turn this into two separate posts. This is the first. July 5, 2014.

The “Quiet American” is not a popular book in the United States of America, but to me it described the dilemma and dangers of being American very well. Continue reading

Icebergs, Islands, and Instruments off Isle de France, North-East Greenland

Leaving all land behind when FS Polarstern sailed for Greenland almost 2
weeks ago, we saw land again for a few hours last Sunday. A small
ice-capped island called Isle de France was ahead of us. Solid ice was to
the west, Continue reading

First steps to Greenland

I am on my way to northern Greenland and just arrived badly time-lagged in Diez near Frankfurt from Philadelphia. Together with fellow scientists and technicians from Germany, Poland, and Canada, Continue reading