Posts Tagged ‘ASTER’

What A Wonderful World: Ice on Ellesmere Island

April 28th, 2017 by Jesse Allen

On top of all the great science they make possible, satellites often produce imagery that is simply beautiful.

This image of Turnabout Glacier on Canada’s Ellesmere Island is a case in point. It shows a classic piedmont glacier that looks almost like pancake batter spilling over a frozen landscape. Piedmont glaciers form when steep valley glaciers spill out into relatively flat plains. Unchained from the constraints of the terrain, the ice flows freely in all directions.

Image Credit: NASA Earth Observatory/ASTER/Jesse Allen

The Advanced Spaceborne Thermal Emissions and Reflection Radiometer (ASTER) instrument on NASA’s Terra satellite acquired an image of the glacier and its surroundings on July 26, 2009. The summertime image shows the glacier free of overlying snow from the previous winter. Banding in the surface of the ice shows different years in which the ice was laid down on the glacier.

Image Credit: NASA Earth Observatory/ASTER/Jesse Allen

In the wider view, you can see glaciers drain out of ice caps between mountain peaks and ridgelines. Many features, including Turnabout, were first formally cataloged in 1957 and 1958 as part of the first International Geophysical Year (IGY). This area is so far north and the weather so cold much of the year that there has been little in the way of human footprints on the landscape. Hence, features had no official names within the scientific community before the IGY.

Humans have, though, made one visible impact on this image. The line on the top left is a contrail from a plane. Contrails form when water-rich exhaust from jet engines freezes into tiny ice crystals at high altitude.

Compare Turnabout to Eugène Glacier in the wider view. Both are classic piedmont glaciers, but Turnabout exits the mountain pass into the Hazen Plain with some obstacles that cause it to twist and turn before ending and draining into the Turnabout River. Eugène Glacier has no such obstacles and spreads out more evenly.

This false-color image was made by combining observations of near infrared, red, and green light. Red indicates vegetation; the chlorophyll in plants reflects much more strongly in the near infrared than other wavelengths.