Professor Tedesco To Study Mysteries Of Supraglacial Lakes In Greenland
Supraglacial lakes are pools of liquid water that collect on the surfaces of glaciers during summer months as a consequence of melting. Because of the huge pressure created by the water over the ice, they can empty out in a matter of hours. Dr. Marco Tedesco, City College Assistant Professor of Earth and Atmospheric Sciences (EAS), wants to find out how much water these lakes store and where it goes.
He and EAS graduate student Nick Steiner are traveling to Greenland in late June and early July to study the connection between the formation of these ponds and the melting of Greenland’s ice sheet. Their project is supported by CUNY, the World Wildlife Foundation and NASA.
After spending a few days in the Greenland village of Iulissat on the west coast, they will be taken by helicopter to the ice sheet, where they will camp for eight days and collect data using a remote controlled boat outfitted with GPS, a fish finder (for measuring depth), a spectrometer, an underwater video camera and a microcomputer. Some of the equipment will measure flow of water in and out of the lakes and will collect water samples for studying the water’s biological and chemical properties, as well.
Professor Tedesco and Mr. Steiner will gather data to measure the depth of the lakes and corroborate satellite measurements of their area. “The extent of the surface of the lakes is easier to retrieve (via satellite) than the depth; that is a major challenge,” Professor Tedesco explains.
“By collecting lake depth data and spectral data on the ground comparable to what is measured by satellites, we can study the differences between the two data sets and understand the errors we have when we use satellite data. Also, we can can develop new approaches and validate them."
Better knowledge of the surface extent and depth of the lakes (and, consequently, their volume) will support understanding of their role in the hydrological system of the ice sheet. “When a lake contains enough water to put a pressure on the ice below, it can open a crack in the ice sheet (several hundred meters thick) and drain through,” Professor Tedesco continues. “When, and if, the water reaches the ice/bedrock interface, it will eventually flow toward the sea along the bottom. In theory, this could cause the ice shield to slip, accelerating toward the sea. But this is still an unsolved mystery."
Professor Tedesco will also collect video and photographic material during the scientific expedition and will document how people live in the Arctic, including their costumes and habits. This material, together with research findings will be incorporated into an interdisciplinary undergraduate course called "Global Warming" offered by CCNY's EAS Department for the Fall 2009 semester and in a course titled “Changing Arctic Environment” that he will teach at the CUNY Graduate Center in conjunction with Professor Allan Frei from Hunter College.
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