US: A University of Wyoming (UW), US, researcher has discovered the use of satellite imagery to map the depth of melt ponds and melt-water stream channels on the surface of the Greenland ice sheet making it a new and more accurate way to keep close watch on that ice sheet’s accelerated rate of melting. Carl Legleiter, a UW assistant professor in the Department of Geography, was lead writer on a study that demonstrated, for the first time, the feasibility of using spectrally based depth retrieval from high-spatial resolution commercial satellite images of supraglacial lakes and streams.
Given instrumentation with sufficient spatial resolution, optical remote sensing can be used to accurately estimate the volume of water stored in large lakes and smaller melt ponds that might go undetected by sensors with larger pixel sizes.“This paper seeks to establish the method of estimating the depth of lakes and streams on the surface of the ice sheet. This remote sensing approach could be a powerful tool for understanding the hydrology of the ice sheet and constraining estimates of sea level rise. Although several previous studies have mapped the locations and depths of relatively large supraglacial lakes from optical image data, none have attempted to retrieve water depth in supraglacial streams,” said Legleiter. “There have been some previous remote sensing studies, but those used larger pixels. There was not as much detail. To our knowledge, ours was the first to look at stream channels. We could see enough detail to map those smaller streams and ponds,” added Legleiter.