Posted by Jim Cochran and Indrani Das
As the Arctic IceBridge season wraps up we can reflect on what was accomplished during this part of the largest airborne survey ever flown of Earth’s polar ice. Although we battled against the forces of nature – Arctic storms, intense winds, thick soupy fog and volcanic ash – a simple count by the numbers shows the campaign was a tremendous success:
Two and a half month spent imaging Arctic sea ice and Greenland outlet glaciers from the air.
The use of two separate planes – a large DC-8 more effective in imaging the broad expanses of sea ice, and a smaller more maneuverable P-3 aircraft that is more effective at imaging the elevation and changes at the base of the outlet glaciers.
A total of 28 science flights completed.
The completion of two types of flights – both high and low altitude flights – designed to utilize different kinds of equipment and to capture different pieces of information on the ice processes and dynamics.
Two kinds of laser altimeter instruments designed to collect the surface elevation of the ice sheet.
A gravimeter, especially designed for use in airplanes, that allows us infer the presence of water or rock under the outlet glaciers of the ice sheet and which will help us better understand the bathymetry of the region.
Four kinds of ice penetrating radar that collected data on the different depths of the ice sheet, from snow accumulation measures at the surface down to a look at the base of the ice sheet.
Over 200 flight hours logged in the air equaling approximately 63000 nautical miles of flight lines flown, equivalent to flying approximately 2.5 times around the equator.
What did we learn? Scientists began immediately to analyze the data and information that was collected from the Arctic and already 3-D images are being created like this one of the Jakobshavn Isbræ. The image shows a laser scan from the Airborne Topographic Mapper (ATM) instrument, one of the two LIDAR (see above) used in the campaign. The 3D illustration of the data collected over the Jakobshavn fjord shows the calving front of the glacier, a cliff more than 300 ft. tall, behind the ice mélange (a dense pack of ice chunks from calved icebergs). The physics of glaciers calving icebergs is very complex and is an interesting problem for scientists. Proper integration of the complex dynamics of calving mechanism in mass balance models is important to determine the rate at which glaciers with calving fronts are losing mass. Such models will improve our ability to predict future sea level rise.
The polar ice processes are extremely complex, but with each new set of data collected and analyzed, our understanding of the changes occurring at the poles will improve. Over the next few months more images and data will be analyzed adding to our understanding of the Arctic processes, and establishing a baseline of information so that with each new season we have more information on: the rate at which the ice thickness over the poles is changing; how the acceleration of the outlet glaciers will affect the ice sheets; and the measure of the extent and thickness of the Arctic sea ice. This data will add to our existing knowledge of global sea level rise and climate change.
Featured image: Map compiled of Spring 2010 campaign flight lines- credit NASA.
Lower image: Credit: Kyle Krabill and the NASA ATM team
Jim Cochran is a geophysicts at Columbia University’s Lamont-Doherty Earth Observatory in the Marine Geology and Geophysics division. Jim has worked extensively on processes under the Earth oceans including several projects in the Arctic Ocean including the Gakkel Ridge, a mid-ocean ridge spreading center in the central Arctic, and the adjacent Amerasian Basin. Jim brings extensive gravity expertise to this project.
Indrani Das is a physicist and atmospheric scientist who has spent the last two years in Alaska studying ice mass loss in the Alaskan glaciers. One area of her study was the Alaskan Wrangell Mountains where she notes the loss of ice mass almost doubled from 2000-2007 when compared to the prior 50 years. She recently moved to New York and jumps at any chance to spend time doing field work and enjoy the beauty of the Arctic glaciers.
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