Tag Archives: glaciers

Petermann Glacier, Ice Islands, and Changing Climate

Posted on July 17, 2012 by | 15 comments

Petermann Glacier is a tidewater glacier in the remote north-west of Greenland. The glacier is grounded at about 600-m below sea level. It has calved two large ice islands, a 4-Manhattan sized island in 2010 and a 2-Manhattan sized one in 2012. These losses cover much of the area shown in this 2009 photo:

Eastern wall of Petermann Fjord as seen from CCGS Henry Larsen’s helicopter in August 2009 with the floating ice shelf. Most of the visible ice shelf has been lost during the 2010 and 2012 calving events. [Photo Credit: David Riedel, British Columbia.]

From selected imagery, I created a short movie (0.7 MB) which shows (a) the 2010 calving, (b) the advance of the new front in 2011 and early 2012, and (c) the 2012 calving. The glacier has moved at a rate of about Continue reading →

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Independence Fjord, Peary, and the First Thule Expedition

Posted on July 4, 2012 by | 3 comments

Independence Day 2012. Independence Fjord 1912. The mapping of northern Greenland.

I am reading 100-year-old travel reports by Danish polar explorers Knud Rasmussen and Peter Freuchen who visited Independence Fjord exactly 100 years ago to resolve a puzzles of Greenland’s geography: Is Peary Land an island or Greenland’s North? It is Greenland, but their detailed report has data I want: glaciers mapped, temperatures recorded, ice described, rocks sampled, musk ox killed. It is all part of an ongoing scientific journey of discovery and writing, but I am getting ahead of my Independence Day and Independence Fjord story:

Map of Greenland as included in the Report of the First Thule Expedition 1912 by Knud Rasmussen also showing contemporary expeditions across the Greenland ice sheet.

The Greenland mapping and early science was done painstakingly via sled dog teams by hardy people and adventurous spirits who had to find and hunt game to avoid death by starvation. Rasmussen, Freuchen, and their Inuit companions Uvdloriaq and Inukitsoq set out over Greenland’s inland ice from Thule on April 19, 1912 with 54 dogs to return 5 months later with only 8 dogs.

Ascent of the Inland ice in April 1912 as the First Thule Expedition starts from Clemens Markham’s Glacier to Independence Fjord. All 4 explorers returned, but only 8 of the 54 dogs did.

This was the First Thule Expedition that was supported by the Thule Trading Post at North Star Bay that Rasmussen and Freuchen had privately established in the fall of 1909. Today it is the location of Thule Air Force Base. My father-in-law served here for a year as a young Airman in the 60ies. It is also where our Nares Strait science party will board the Canadian Coast Guard Ship Henry Larsen Aug.-1, 2012. I am thinking of Peter Freuchen and his Inuit wife Naravana, Knud Rasmussen, and Independence Fjord on this Independence Day.

The Freuchen family on a visit to Denmark: Naravana, Pipaluk, Peter, and Mequsaq [Source: Freuchen, P., 1953: Vagrant Viking. Julian Messner Inc., NY, 312 pp.]

Independence Fjord in the summer of 2007 as seen from Kap Moltke looking south. [Source: web]

Independence Fjord in north-east Greenland was named by Robert E. Peary on America’s birthday 120 years ago on July 4, 1892 when he was the first white person to get there. Prehistoric people of the Independence cultures left artifacts from 3000 years ago. Hunting was good then, too. The 120 year old photograph of Peary shows him standing atop Navy Cliff next to a cairn with two Star Spangled Banners fluttering in the wind. The view eastward is along the 120 mile (200 km) long and 19 miles (30 km) wide Independence Fjord that opens into the Greenland Sea.

Peary at Navy Cliff, Greenland on July 4, 1892 atop Independence Fjord. [Photo Credit: Bowdoin College]

Note left by R.E. Peary on July 5, 1892 at a cairn at Navy Cliff overlooking Independence Fjord which he named here such. The darker pencil at the bottom is Peter Freuchen’s.

Peter Freuchen of the Thule expedition recovered Peary’s note 100 years ago. He then made and left a copy, added his own note, and headed home to Thule, Greenland. Besides checking on Peary the two Danes were also looking for a lost Danish expedition led by Einar Mikkelsen, who in turn was looking to recover the bodies of two Danish explorers of Independence Fjord, Ludvig Mylius-Erichsen and Niels Peter Hoegen-Hagen who had died nearby in 1907. Almost all these explorers have mountains, glaciers, land, and capes named after them or their sponsors, only Independence Fjord is different.

Independence Fjord celebrates the birthday of a young nation, the idea of a painfully evolving democracy, work still in progress. Peary may have made many claims that were not always supported by the evidence he presented, such as claiming to have reached the North Pole. He was no scientist, but a manager driving hard to secure funds, a ruthless self promoter, and autocrat assigning native women to men of his liking. But in this one instance of naming one of Greenland’s grand fjords Independence Fjord, he did good. Recall that this was the time when unelected kings, queens, generals, and dictators were ruling over expanding colonial empires. It was a few years before World War I and its follow-up World War II that caused global devastation to usher in a new set of world powers. The idea of independence is symbolized both in Independence Fjord and Independence Day. Both celebrate the same thing: freedom. There will be fireworks tonight …

P.S.: Some maps

North-East Greenland [Source: web]

MODIS-Terra imagery of Independence Fjord for June 18, 2012. Top panel shows reflectance in the near infra-red (1240 nm) emphasizing land while the bottom panel shows reflectance in the visible red (865 nm) emphasizing ice. The red dot indicates Navy Cliff, the vantage point at the western terminus of Independence Fjord with Academy Glacier to its south-east and Sophie Marie Glacier to its north-west.

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Greenland’s Warming, Melting, and Sliding to Sea

Posted on June 27, 2012 by | 12 comments

Greenland is warming, Greenland’s warming is melting its ice, and Greenland melting ice is raising global sea level. All true, but it all has happened before during the last 100 years or so. Our technology to extract small signals buried deep in noise from both our backyard and remote Greenland is unprecedented. This skill should not fool us, that the large changes that we see in Greenland and elsewhere have not happened before. They have, but memory is a fickle thing, as “new” is exciting, while “old” is often forgotten and considered unimportant. Those who live in the past are doomed to miss the present, those who ignore the past, are doomed to repeat it. We need to learn from the past, live in the present, and prepare for the future.

Preparing for an expedition to Nares Strait between northern Greenland and Canada in about 5 weeks, I am exploring temperature data from land, satellites, and ocean sensors to get a feel for what has changed. I started with data from weather stations such as the U.S. Air Force Base Thule , Canada’s former spy station Alert, and Denmark’s Station Nord about 700-1000 miles from the North Pole. So, it is cold up there:

Annual cycle of air temperature (bottom panel) from south to north at Thule (red), Grise Fjord (green), Alert (blue), and Cap Morris Jesup. Data years (top panel) for each year day are degrees of freedom. For each place two temperature curves indicate upper and lower limits of the climatological mean temperature for that day at 95\% confidence.

Well, we knew that, but the real question is: Has anything changed? Has Global Warming reached Greenland? The plot above does not tell, but this one does:

Annual averages and trends of air temperature anomalies for the 1987-2010 period for (top to bottom) Station Nord (Greenland), Alert (Canada), Grise Fjord (Canada), and Thule (Greenland). Scales are identical. The trends are fitted to daily, not annual data. The annual averages are shown for display purposes only.

To some it screams: “Warming, melting, Greenland is surging to sea.” [It is, but it did so before.]

There is lots of fancy signal processing that goes into this (see Tamino or a class I teach) to make a firm statement:

The air around northern Greenland and Ellesmere Island has warmed by about 0.11 +/- 0.025 degrees Celsius per year since 1987. North-west Greenland and north-east Canada are warming more than five times faster than the rest of the world.

This must be huge (yes, it is), it must have an effect on the Greenland ice sheet (yes, it does), and this must raise sea level (yes, perhaps 10 cm or 3 inches in 100 years, Moon et al., 2012).

Now where is the catch?

The catch is that my records all start in 1987, because that is the period for which I have actual measurements from all those stations. My satellite record is even shorter: it starts in 2000, but with lots of work can be extended back to 1978. And my ocean record is shorter yet: it starts in 2003. There just are no other hard data available from north-west Greenland.

So, does this mean we are stuck with the gloom and doom of a short record?

No, but we have to leave the comforts of hard, modern data with which to do solid science. People have to stick out their necks a little by making larger scale interferences. Based on the 1987-2010 results shown above, I can now say that trends and year-to-year variations are all similar in Alert, Thule, Kap Morris Jesup, etc., etc., so I will use the 60 year Thule record to make statements that somewhat represent all of Nares Strait. I could also start looking for softer and older data. With soft data I mean sketchy ship logs kept by whalers, tense expedition reports of starving explorers (Lauge Koch, Knud Rasmussen, Peter Freuchen), and imperial expeditions (George Nares, Adolphus Greely).

Further south there are a few ports where government or trading authorities started records early. The current capital of Greenland, Nuuk (formerly Godthab) is such a place. The Nuuk record starts 1881. And what I find is that the current warming in Greenland has happened just as dramatic as it does now in the 1920ies and 1930ies [well, except for the 2010 spike, but that story is still ongoing]:

Data from Nuuk, southern Greenland, where the temperature record goes back to 1881 (monthly data from NASA/GISS). The dashed line indicates 1987.

The trend is statistically significant, about 0.008 +/- 0.03 degrees centigrade per year or about 10 times smaller than what it is for northern Greenland starting in 1987. So the devil of Greenland warming, melting, and sliding to sea is in the details or records that are too short. The Global Warming signal is in there, but how much, we do not know and perhaps cannot know. Furthermore, most of the globe of “Global Warming” is covered by water and the ocean warming we know little about. Recall, my ocean record off northern Greenland only starts in 2003 and ends in 2009 or 2012, if we recover computers, sensors, and data from the bottom of Nares Strait this summer.

Greenland’s data and physics of ice, ocean, and air are exciting and all show dramatic change. To me, this is a big and fun puzzle, but one has to be careful and humble to avoid making silly statements for political purposes that are not supported by data. Do I think Global Warming is happening? Absolutely, yes. Do I think it is man-made? Probably. What do I do about it? I ride my bicycle to and from work every day. And that’s what I do next … bicycle home.

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Posted in Global Warming, Ice Cover

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Last Image of Nares Strait from Europe’s Environmental Satellite

Posted on May 9, 2012 by | Leave a comment

The European Space Agency announced today that one of its primary environmental satellites died. For over a months now engineers could neither receive data nor send commands to the 10-year old veteran of earth science research whose design life was 5 years. The last image received for my study area between northern Greenland and Canada shows Petermann Gletscher and ice-covered Nares Strait:

The rectangle between Franklin Island, Greenland and Ellesmere Island, Canada shows the site where in August 2012 we hopefully will recover data from an array of ice and ocean sensing equipment that we put there in 2009.

It was during this 2009 International Polar Year expedition to Nares Strait that I discovered satellite remote sensing in a new way, that is, accessing the raw digits sent down to earth from the NASA’s Aqua and Terra satellites that contain Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. These two sensors are as old or older than its European companion. MODIS are now the only optical sensors at better than daily resolution which check the land, ocean, and ice now that the European satellite is not talking with us anymore.

For me, the most spectacular use of Europe’s EnviSat was its ability to document how the 2010 Petermann Ice Island wiggled its way out of its constraining fjord into Nares Strait. A movie of daily radar images is attached:

Petermann Ice Island 2010 slow movement through Petermann Fjord, break-up on Joe Island, and swift movement southward in Nares Strait. Click on image to start movie.

Unlike its Canadian counterpart, RadarSat, the imagery from the European radar (ASAR) was distributed widely, free of charge, and became useful to research communities and a wider public. The Danish Meteorological Institute provides an archive of imagery from both US and European satellites for all of coastal Greenland that just lost its European imagery (http://ocean.dmi.dk/arctic/modis.uk.php). Unlike the now defunct EnviSat, RadarSat is a for-profit commercial enterprise unaffordable to scientists or a public. The Canadian government funded development, launch, and initial data processing before giving it away to a private corporation. Ironically, the largest paying customer for its expensive products is the Canadian Government, but the data are rarely used for public education or research. They may as well be secret.

So, the demise of EnviSat is sad news. It removes a semi-public eye in the sky. Lets hope, that its replacement by the European Space Agency receives the urgent attention that it deserves.

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Greenland’s Glaciers, Science, Sea-Level, and Teachers

Posted on May 4, 2012 by | 1 comment

Science Magazine hit climate change hard today. They cover how Greenland’s glaciers and ice sheets change as they interact with the ocean and contribute to sea-level rise feature in 3 related stories. The reality check of these three stories puts a damper on the usual doomsday scenarios of those whose skill is limited to grabbing public attention to move a political agenda. Real science works differently:

May-4, 2012 Science Magazine Cover: A jumble of icebergs forms in front of the heavily crevassed calving front of Jakobshavn Isbræ, one of the fastest outlet glaciers draining the Greenland Ice Sheet. The ~5-kilometer-wide ice front rises ~80 meters out of the water and extends more than 600 meters underwater. Recent research shows that the speeds of Greenland glaciers are increasing. See page 576. [Photo Credit: Ian Joughin, APL/UW]

The solid new research is that of Twila Moon, a graduate student at the University of Washington whose dissertation work relates to the evolution of Greenland’s outlet glaciers over the last 10 years. She uses data from Canadian, German, and Japanese radars flown on satellites. She applies fancy mathematics to the data and feds data and mathematics into modern computer codes. And with all that, she cracks the puzzle on how fast more than 200 of Greenland’s largest glaciers go to town, eh, I mean, to sea. Furthermore, she shows how this flow has changed over the last 10 years.

Twila Moon, graduate student and scientist at the University of Washington and first author of “21st-Century Evolution of Greenland Outlet Glacier velocities” that appeared in Science Magazine on May-4, 2012. [Photo Credit: APL/UW website]

Back in the days of 2008, crude, but simple back-on-the-envelope calculation suggested that Greenland contributes 0.8-2.0 meters to global sea-level rise by 2100. In stark contrast, the 2000-2010 data now reveals, that even the low-end estimate is too high by a factor of 10. A glacier here or there may accelerate at a large rate to give the 0.8-2.0 m, but these rates do not occur at the same time at all glaciers. Ms. Moon’s more comprehensive and careful analyses of accelerating glaciers bring down Greenland’s contributions to sea-level rise to below 0.1 m by 2100, that comes to about 1 mm/year or an inch in 30 years.

A commentary written by Professor Richard Alley relates to the ice-sheets that feed these glaciers. Dr. Alley is famous for his work on Greenland’s ice sheet as he participated in 2-Mile Time Machine, a project that revolutionized the way that we view climate and its variability the last 100,000 years. The title refers to the 2-mile long ice-core from Greenland’s ice-sheet that trapped and stored air and stuff from the last 100,000 years. Dr. Alley is also featured in Andrew Revkin’s dot-earth blog of the New York Times as the Singing Climatologist. His comment on “Modeling Ice-Sheet Flow” references Ms. Moon’s observations as evidence that ice sheets change quickly. It also contains the sentence that “The lack of a firm understanding of ice-sheet-ocean interaction, constrained by reliable ocean data, remains a critical obstacle to understanding future changes.” I could not agree more with this sentiment, these data are darn hard to come by … not as hard as getting to the bottom of the 2-mile time machine, though.

While Ms. Moon addressed changes in Greenland’s glaciers, Dr. Alley addressed the ice-sheets feeding those glaciers, another comment by physical oceanographer Dr. Josh Willis of NASA’s Jet Propulsion Laboratory relates to the sea-level changes caused by accelerating glaciers to make “Regional Sea-Level Projections.” He works mostly on massive computer models which devour massive amounts of data to get climate right. Sometimes this works, sometimes is does not, but he does comment that these earth system models give sea-level projections that are a factor 2 smaller than those derived from statistical relations and semi-empirical models using surface temperature and radiative forcing to extrapolate past trends into the future. The difference probably relates to smaller and more regional processes that involve the physics of ocean circulation and its interaction with ice-shelves off Antarctic and Greenland.

Dr. Josh Willis conducting an oceanographic experiment studying sea temperatures between New Zealand and Hawaii. [Credit: JPL/NASA]

My great oceanography hero, Henry Stommel of Woods Hole oceanographic Institution once wrote in his “View of the Sea,” that “Science is both an individual and a social activity.” I am sure that graduate student Ms. Moon, NASA researcher Dr. Willis, and veteran professor and science communicator Prof. Alley all work hard and lonely at night some nights … and party hard while discussing science and adventures over a beer, dinner, coffee in some city, remote field, or on a ship. The one group of people missing in this picture are … the science teachers, that is, those dedicated, over-worked, and under-paid professionals who encourage, motivate, and helped us to become scientists before we went to college.

The editorial of this week’s Science Magazine is entitled “Empowering Science Teachers.” It compares the social and professional status of pre-college science teachers in Finland and the USA. I will only say in the words of Anne Baffert, chemistry teacher at Salpointe Catholic High School in Tucson, Arizona, that too many science “… teachers work in a command-and-control environment, managed by those who lack any real understanding of how to improve the system.” The editorial suggests on how scientists can improve science teaching, such as “… active involvement in science through structured collaborations with scientists …” Apparently, Finland succeeds while we in the USA are challenged to get our graduate students into a pre-college class room teaching. More stuff for me to munch on here …

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