A.MALIN Johansson† and IAN A. Brown
This paper is accepted for publication in Remote Sensing Letters.
Melt water gathered in supra-glacial lakes on the Greenland ice sheet contributes to reduced basal friction by input of water from the surface to the bed during the melt season. Supra-glacial lakes change both on an annual as well as inter-annual timescales. The high temporal resolution and moderate spatial resolution Moderate Resolution Imaging Spectro-radiometer (MODIS) images can be used to capture annual changes on the highly transient / fast draining lakes. However, MODIS imagery lack the ability to penetrate clouds. Using Envisat synthetic aperture radar (SAR) winter images we show that SAR images can be used to identify seasonal/inter annual changes in lake area. Furthermore, winter SAR images identify lakes obscured to optical data by ice and snow cover. However, the SAR imagery systematically failed to discriminate narrow lakes and lakes in corrugated topography. Thus SAR images can be used as a complement to existing visible-near infrared data but do not offer a viable replacement.