Author Archives: Andreas Muenchow

Thule on My Mind: Deep Water Port and Air Force Base

Posted on June 6, 2013 | 19 comments

I am an air force brat. My father and my father-in-law enlisted in the German and US Air Forces, respectively. They served during the Cold War when I was born in 1961 a few month after the Berlin Wall went up. My father-in-law was stationed in Thule, Greenland, a northern forward base with radars to detect ballistic missiles, fighter jets to intercept planes, and bombers to retaliate in nuclear war. About 60 years later, the fighter jets, bombers, and communist threat are all gone, but the base is still there, and to me it is the gateway to North Greenland. Both US and Canadian Coast Guard icebreakers call its port to receive or discharge crews and scientists such as myself in 2003, 2006, 2007, 2009, and 2012.

An F-102 jet of the 332d Fighter-Interceptor Squadron at Thule AFB in 1960. [Credit: United States Air Force]

An F-102 jet of the 332d Fighter-Interceptor Squadron at Thule AFB in 1960. [Credit: United States Air Force.]

Today about 58,000 people live on Greenland spread Continue reading →

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Posted in Greenland, Polar Exploration, Uncategorized

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Land-Fast Ice Cover off North Greenland: Will NASA bite?

Posted on May 17, 2013 | 7 comments

When a large outlet glacier of North Greenland (Petermann Gletscher) discharged an ice island four times the size of Manhattan in August of 2010, the United States’ Congress held formal inquiries on its cause within days of the event. Congressmen, scientists, and the global media speculated that this event and concurrent severe droughts in Russia and floods in Asia were tied to record-breaking air temperatures and global warming. Reviewing available data, Johnson et al. (2011) cautioned that most melting of floating ice shelves such as Petermann Gletscher is dominated by physical ocean processes below, not above the ice (Reeh, 2001, Rignot and Steffen, 2008). The National Journal asked me to write an essay to answer the question: “Is Climate Change Causing Wild Weather?” which I answered with a nerdy No, but …. Motivated by questions asked during the congressional hearing, I showed that waters in Petermann Fjord (a) originate from the Arctic Ocean to the north, (b) contain heat of Atlantic origin, and (c) have warmed significantly since 2003 (Muenchow et al., 2011).

Petermann Gletscher from MODIS Terra. Repeat NASA along-glacier flight tracks are shown in the left and middle panels. White line across the glacier are ICESat tracks. Thick black line across the glacier near y = 0 km is the grounding line location from Rignot and Steffen (2008). Dark areas within 2 km off the western wall are mountain shadows.

Petermann Gletscher from MODIS Terra. Repeat NASA along-glacier flight tracks are shown in the left and middle panels. White line across the glacier are ICESat tracks. Thick black line across the glacier near y = 0 km is the grounding line location from Rignot and Steffen (2008). Dark areas within 2 km off the western wall are mountain shadows.

When I reported here that the same glacier discharged yet another ice island in July 2012, this one “only” twice the size of Manhattan, I was not so sure anymore, that this was merely another extreme event caused by natural processes. Continue reading →

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Posted in Global Warming, Greenland, Ice Cover, Ice Island, Petermann Glacier

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The Turbulence of Van Gogh and the Labrador Shelf Current

Posted on May 8, 2013 | 3 comments

Vincent Van Gogh painted his most turbulent images when insane. The Labrador Current resembles Van Gogh’s paintings when it becomes unstable. There is no reason that mental and geophysical instability relate to each other. And yet they do. Russian physicist Andrey Kolmogorov developed theories of turbulence 70 years ago that Mexican physicist applied to some of Van Gogh’s paintings such as “Starry Sky:”

Vincent Van Gogh's "Starry Sky" painted in June 1889.

Vincent Van Gogh’s “Starry Sky” painted in June 1889.

The whirls and curls evoke motion. The colors vibrate and oscillate like waves that come and go. There are rounded curves and borders in the tiny trees, the big mountains, and the blinking stars. Oceanographers call these rounded curves eddies when they close on themselves much as is done by a smooth wave that is breaking when it hits the beach in violent turmoil.

Waves come in many sizes at many periods. The wave on the beach has a period of 5 seconds maybe and measures 50 meters from crest to crest. Tides are waves, too, but their period is half a day with a distance of more than 1000 km from crest to crest. These are scales of time and space. There exist powerful mathematical statements to tell us that we can describe all motions as the sum of many waves at different scales. Our cell phone and computer communications depend on it, as do whales, dolphins, and submarines navigating under water, but I digress.

The Labrador Shelf Current off Canada moves ice, icebergs, and ice islands from the Arctic down the coast into the Atlantic Ocean. To the naked eye the ice is white while the ocean is blue. Our eyes in the sky on NASA satellites sense the amount of light and color that ice and ocean when hit by sun or moon light reflects back to space. An image from last friday gives a sense of the violence and motion when this icy south-eastward flowing current off Labrador is opposed by a short wind-burst in the opposite direction:

Ice in the Labrador Current as seen by MODIS-Terra on May 3, 2013.

Ice in the Labrador Current as seen by MODIS-Terra on May 3, 2013. Blue colors represent open water while white and yellow colors represent ice of varying concentrations.

Flying from London to Chicago on April 6, 2008, Daniel Schwen photographed the icy surface of the Labrador Current a little farther south:

Ice fields seen in Labrador Current April 6, 2008 from a plane. [Photo Credit: Daniel Schwen]

Ice fields seen in Labrador Current April 6, 2008 from a plane. [Photo Credit: Daniel Schwen]

Ice in the Labrador Current as seen by MODIS-Terra on April 6, 2008. Blue colors represent open water while white and yellow colors represent ice of varying concentrations.

Ice in the Labrador Current as seen by MODIS-Terra on April 6, 2008. Blue colors represent open water while white and yellow colors represent ice of varying concentrations.

The swirls and eddies trap small pieces of ice and arrange them into wavy bands, filaments, and trap them. The ice visualizes turbulent motions at the ocean surface. Also notice the wide range in scales as some circular vortices are quiet small and some rather large. If the fluid is turbulent in the mathematical sense, then the color contrast or the intensity of the colors and their change in space varies according to an equation valid for almost all motions at almost all scales. It is this scaling law of turbulent motions that three Mexican physicists tested with regard to Van Gogh’s paintings. They “pretended” that the painting represents the image of a flow that follows the physics of turbulent motions. And their work finds that Van Gogh indeed painted intuitively in ways that mimics nature’s turbulent motions when the physical laws were not yet known.

There are two take-home messages for me: First, fine art and physics often converge in unexpected ways. Second, I now want to know, if nature’s painting of the Labrador Shelf Current follows the same rules. There is a crucial wrinkle in motions impacted by the earth rotations: While the turbulence of Van Gogh or Kolmogorov cascades energy from large to smaller scales, that is, the larger eddies break up into several smaller eddies, for planetary-scale motions influenced by the Coriolis force due to earth’s rotation, the energy moves in the opposite direction, that is, the large eddies get larger as the feed on the smaller eddies. There is always more to discover, alas, but that’s the fun of physics, art, and oceanography.

Aragón, J., Naumis, G., Bai, M., Torres, M., & Maini, P. (2008). Turbulent Luminance in Impassioned van Gogh Paintings Journal of Mathematical Imaging and Vision, 30 (3), 275-283 DOI: 10.1007/s10851-007-0055-0

Ball, P. (2006). Van Gogh painted perfect turbulence news@nature DOI: 10.1038/news060703-17

Wu, Y., Tang, C., & Hannah, C. (2012). The circulation of eastern Canadian seas Progress in Oceanography, 106, 28-48 DOI: 10.1016/j.pocean.2012.06.005

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Posted in Oceanography

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Petermann Photos, Places, and People

Posted on May 2, 2013 | 7 comments

Petermann Gletscher sent off Manhattan-sized islands of ice in 2010 and 2012 that now litter the eastern seaboard of Canada from its farthest northern Ellesmere Island to its farthest eastern Newfoundland. The ice is streaming south along thousands of miles within icy Arctic waters. Petermann Gletscher itself is flat, hard to grasp by the naked eye, its endless expanse of white vanishes into the horizon when we look towards the Greenland Ice Sheet ALONG the glacier:

North-eastern section of Petermann Glacier on Aug.-11, 2012, the meandering river is the centerline, view is almost due east. [Photo Credit: Canadian Coast Guard Ship Henry Larsen.]

North-eastern portion of Petermann Glacier on Aug.-11, 2012, the meandering river is the centerline, view is almost due east with Kap Fulford and Kap Agnes on the left center and Daugaard Jensen Land in the background on the right. [Photo Credit: Canadian Coast Guard Ship Henry Larsen.]

Next, lets look ACROSS Petermann from roughly the same latitude. This perspective is more dramatic as vertical cliffs give shape, cliffs are cut by smaller side-glaciers. More specifically, we see the CCGS Henry Larsen helicopter flying down Belgrave Glacier as we look across Petermann which flows from the Greenland Ice Sheet on the left out to sea on the right. On the other (south-western) side we see Faith Glacier in the background about 10 miles away.

Seaward front of Petermann Glacier Aug.-11, 2012. View is from a small side-glacier towards the south-east across Petermann Fjord with Petermann Gletscher to the left (east). [Photo Credit: Erin Clarke, Canadian Coast Guard Ship Henry Larsen]

Seaward front of Petermann Glacier Aug.-11, 2012. View is from a small side-glacier (Belgrave Gl.) towards a similar glacier (Faith Gl.) across Petermann Fjord with Petermann Gletscher flowing from the left out to sea on the right. [Photo Credit: Erin Clarke, Canadian Coast Guard Ship Henry Larsen]

Contrasting large Petermann Gletscher, the many smaller glaciers on both its sides evoke drama as ice plunges down from 3000 feet above in a rage of forms, colors, and shapes. These side glaciers have their own side glaciers that sometimes rival the Alpine glaciers in Europe, Asia, and the Americas that most of us are more familiar with.

Some side glaciers have names, but they are rarely seen on maps and charts. The side glaciers are mapped, but photos are hard to find. Flying over them last year, I was utterly lost. Reviewing photos now, I remember people, smells, computer troubles, and exciting ocean discoveries. Nevertheless, I am hard pressed to place the places we saw on a map or name them. Distances are deceiving, the air is clean and 50-80 miles of visibility are common. A moment later, I cannot see the other side of the ship as we are suddenly in clouds and fog. Everything is always in motion, the ice, the water, the ship, the clouds, all of this without strong reference points like the exit or distance signs on a Turnpike, Interstate, or Autobahn.

Northern Kennedy Channel near the entrance to Petermann Fjord with Kap Morton in cloud banks. [Credit: Andreas Muenchow]

Northern Kennedy Channel near the entrance to Petermann Fjord with Kap Morton in cloud banks. [Credit: Andreas Muenchow]

And along comes Espen Olsen, a frequent contributor to Neven’s Arctic Sea Ice blog and forums, and discovers a plethora of names that I can check, google, and use to remember expeditions to Petermann over the last 10 years with many good friends. So with his help and that of other explorers like Lauge Koch, Tony Higgins, and the collected wisdom of the U.S. Defense Mapping Agency, I labeled some prominent glaciers and capes on an Aug,-21, 2012 MODIS-Terra image that I constructed from data that NASA provide to anyone free of charge. I chose this image and time, because the 2012 ice island is already in Nares Strait and thus out of sight:

Names of glaciers, capes, islands in Petermann Region over MODIS of Aug.-21, 2012.

Names of glaciers, capes, islands in Petermann Region over MODIS of Aug.-21, 2012.

Espen tells me that his Danish sources are protected by copyright (I still like to cite them), but the aviation maps of the U.S. military are in the public domain and can be downloaded from the University of Texas in Austin Library, e.g.,

Petermann Gletscher and surroundings extracted from U.S. Defense Mapping Agency Chart ONC A5 (January 1991).

Petermann Gletscher and suroundings extracted from U.S. Defense Mapping Agency Chart ONC A5 (January 1991).

while the modified version of Figure-2 from Dr. Tony Higgins 1990 publication is available at the Alfred Wegener Institute. Nevertheless, it should only be used for non-profit educational purposes or as a reference:

Petermann Gletscher extend and topography from 1953 through 1978 (from Higgins, 1990) with 2012 terminus position drawn in by hand.

Petermann Gletscher extend and topography from 1953 through 1978 (from Higgins, 1990) with 2012 terminus position drawn in by hand.

With all these details out-of-the-way, we can now start placing photos into places and add names to them. Perhaps others like Espen Olsen can write or edit Wiki entries or correct the false latitude and longitudes that populate the many databases that provide such information on the web. Over the next weeks and months I will try to post as many photos of Petermann’s natural beauty along with an evolving MODIS map that names and shows places. Here are just a few teasers without further comment except what’s in the captions.

The merging of Sigurd Berg and Hubert Glaciers which discharge into Petermann Gletscher on its eastern wall. The view is landward towards the north-east as the helicopter flies in from Petermann. [Credit: Barbara O'Connell, Canadian Coast Guard]

The merging of Hubert (left) and Sigurd Berg (right) Glaciers which discharge into Petermann Gletscher on its eastern wall. The view is landward towards the north-east as the helicopter flies in from Petermann. [Credit: Barbara O’Connell, Canadian Coast Guard]

Petermann Gletscher and Fjord in Aug.-2012. View is to the north-west with Faith Glacier (top left) and Kap Lucie Marie (top right) showing the western wall of Petermann. [Photo Credit: CCGS Henry Larsen]

Petermann Gletscher and Fjord in Aug.-2012. View is to the north-west with Faith Glacier (top left) and Kap Lucie Marie (top right) showing the western wall of Petermann. [Photo Credit: CCGS Henry Larsen]

Looking down Belgrave Glacier discharging into Petermann Gletscher at its terminus in Aug. 2012 [Credit: CCGS Henry Larsen]

Looking down Belgrave Glacier discharging into Petermann Gletscher at its terminus in Aug. 2012 [Credit: CCGS Henry Larsen]

Higgins, A.K. (1990). Northern Greenland glacier velocities and calf ice production Polarforschung, 60, 1-23 Other: 0032-2490

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Posted in Greenland, Ice Island, Nares Strait 2012, Petermann Glacier

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Cockpit’s View of Greenland’s Glaciers, Ice-Sheets, and Sea-Ice

Posted on April 10, 2013 | 4 comments

The glaciers and ice-sheets of Greenland retreat and melt in a warming world. Towering almost 3000 meters above sea level the ice-sheet is so thick and heavy that it depresses the bedrock underneath below current sea-level. Monitoring the ice-sheet, outlet glaciers, and sea ice of Greenland, NASA’s Operation IceBridge flies aircraft packed with radars, lasers, and optical sensors each spring and summer all over Greenland. There are exciting blogs written by the scientists aboard as they live and work out of Greenland. And today I discovered that they also provide video feeds as their plane conducts measurements. Here is an example from yesterday:

I am not entirely sure on the exact location off south-east Greenland, perhaps this is the area near Helheim Glacier, e.g.,

Greenland's bed-rock elevation from Bamber et al. (2003) digital elevation model based on remotely sensed surveys of the 1970ies and 1990ies gridded at 5 km resolution.

Greenland’s bed-rock elevation from Bamber et al. (2003) digital elevation model based on remotely sensed surveys of the 1970ies and 1990ies gridded at 5 km resolution.

but this will become clear as soon as the data are released to the public. This usually happens within a few months. The wide and open data distribution and access is one of the greatest things about this mission. If you want to see where the plane is now, this is the screenshot I took just now (site)

Locations of NASA's P3 air plane near Jacobshavn Isbrae on April-10, 2013.

Locations of NASA’s P3 air plane near Jacobshavn Isbrae on April-10, 2013.

The evolution of Jacobshavn Isbrae retreat from 1851 through present. [From NASA's Earth Observatory]

The evolution of Jacobshavn Isbrae retreat from 1851 through present. [From NASA’s Earth Observatory]

Jacobshavn lost its buttressing ice-shelf during the last decade and now rapidly discharges ice from the Greenland ice-sheet directly into the ocean at a rapid rate. Most likely, the ice-shelf was melted by the ocean from below (Holland et al., 2008). This type of accelerated discharge raises global sea-level, because ice previously sitting on Greenland’s bedrock moves into the ocean where it eventually will melt. In response to the ice removed, the bed-rock rises as there is less mass above it to hold it down (Khan et al, 2010). All this has actually been measured by satellites (mass-loss) and ground-based GPS (bed-rock response). We live in a dynamic and rapidly changing world where our sensors and software show new patterns of physics that have never been seen before. There is so much more to discover …

Csatho, B., Schenk, T., Van Der Veen, C., & Krabill, W. (2008). Intermittent thinning of Jakobshavn Isbræ, West Greenland, since the Little Ice Age Journal of Glaciology, 54 (184), 131-144 DOI: 10.3189/002214308784409035

Holland, D., Thomas, R., de Young, B., Ribergaard, M., & Lyberth, B. (2008). Acceleration of Jakobshavn Isbræ triggered by warm subsurface ocean waters Nature Geoscience, 1 (10), 659-664 DOI: 10.1038/ngeo316

Khan, S., Wahr, J., Bevis, M., Velicogna, I., & Kendrick, E. (2010). Spread of ice mass loss into northwest Greenland observed by GRACE and GPS Geophysical Research Letters, 37 (6) DOI: 10.1029/2010GL042460

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Posted in Greenland

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