NASA Creates The First Map Showing Thawed Areas Beneath The Greenland Ice Sheet

First Posted: Aug 05, 2016 03:18 AM EDT

NASA creates the first map that identifies which parts beneath the Greenland ice sheet are frozen and thawed. This will help in predicting how the ice sheet will react to a climate change. It is also the first time to map beneath the surface of a huge block of ice.

The researchers have been trying to discover what's happening underneath for a long time. This is needed for foreseeing the sheet's movements in the future. Joe MacGregor, the NASA Goddard glaciologist, and the team leader said that they are interested in understanding how the ice sheets flow and how it will behave in the future. He further said that if the ice at its bottom is at the melting point temperature, or thawed then there could be enough liquid water there for the ice to flow faster. This influences how quickly it responds to climate change, according to NASA.

The study was printed in the Journal of Geophysical Research-Earth Surface. The team investigated the basal thermal state in four various ways. They studied results of the ice sheet using data from eight recent computer models. These predict the bottom temperatures. Then, they studied the layers that comprise of the ice sheet. This indicates where the bottom of the ice is melting faster. They are detected by radars onboard NASA's Operation Ice Bridge aircraft. The researchers also identified at where the ice surface speed measured by satellites exceeds its "speed limit." This is the maximum velocity at which the ice could flow and still be frozen to the rock beneath it. Lastly, the team looked for rugged surface terrain that has ice sliding over a thawed bed by studying the imagery from the Moderate Resolution Imaging Spectroradiometers on the NASA Terra and Aqua satellites.

"Each of these methods has strengths and weaknesses. Considering just one isn't enough. By combining them, we produced the first large-scale assessment of Greenland's basal thermal state," said MacGregor.

The Greenland ice sheet is also referred to as inland ice or an ice cap. It is the second largest ice body in the world with about 1,710,000 square kilometers ice covering next to Antarctic Ice Sheet. That is approximately 80 percent of the surface of Greenland. The thickness of the ice is more than 2 kilometers and over 3 kilometers at its thickest point.

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