Posted by Indrani Das
We have switched aircraft and locations for this phase of the IceBridge Mission. The first month of the mission we flew a large DC-8 aircraft and were based in the U.S. Air Force base in Thule in the Northwest section of Greenland. The aircraft and location were a good match for surveying Arctic sea ice during the time of year when it is expected to be at its largest extent.
As we move into the spring season in the Arctic it is time to change the focus to the second phase of the Arctic campaign, the changing glaciers. We will be flying over outlet glaciers using a smaller P3 aircraft, measuring changes in acceleration and elevation. We will operate from Kangerdlussuaq, further South of Thule on the West side of Greenland.
Three of the glaciers we will focus on have been changing quickly – Helheim, in East Greenland, and Jacobshaven and Kangerdlussuaq in Southwest Greenland – but we will be measuring and assessing many other glaciers as well. Flying over these outlet glaciers can be a bumpy flight with lots of maneuvering. To add another element of challenge we must navigate around the volcanic ash from Iceland’s Eyjafjallajokull volcano as we fly since it has recently shifted into our airspace.
It is incredible to see the calving faces of these remarkable outlet glaciers; their size is immense. These unstoppable glaciers are so large that as they slip and slide over their beds they generate seismic waves and cause glacial earthquakes as they move; all of which can be recorded by a seismometer. As the ice retreats, the glaciers leave behind carved landscapes. One of the glaciers we flew over today is the Midgard glacier on the east coast of Greenland.
This is my favorite picture of the Midgard glacier where one can see the extent of the glacier in the last ice age from the coloration change. You can really see how much the glacier has retreated since that time. I heard on the plane that the Midgard glacier was discovered serendipitously by someone flying near it and taking a wrong turn. The views of this glacier are amazing. It appears that one of its tributaries is surging. Surges are brief periods of rapid ice movement often causing deep crevassing or cracking on the surface of the glacier. Surging can be the result of slipping at the base of the glacier causing it to suddenly quicken. Water from surface melt ponds emptying in melt tubes and reaching the base of these glaciers can be the cause of this slipping.
The changes in the Arctic, and in Greenland’s ice sheet, attracts a lot of science researchers. Whenever possible the IceBridge mission tries to provide overflight data collection for other research missions that are in the area. Recently we provided overflight for the European CryoSat-2, and today we passed over a ground team completing an overland traverse collecting snow and ice core data. The overflight data we collect can be used to validate/calibrate their location information. The DSM camera on board the P3 captured images of the team snow mobiles, snow probes and snow pits as the team went about their work. With the intense focus placed on Arctic through IceBridge and this mission we hope to develop a more robust understanding of not only the processes taking place, but the factors that are contributing to the changes in order to improve our climate models.
Featured image: Image of surging tributary of the Midard glacier showing the heavy crevassing in the ice stream.
In body of text: This image of Midgard glacier shows the extent of glacial ice in the last ice age. Credit Indrani Das
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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