Monitoring Lake Ice (VIDEO) University of Waterloo This video is under embargo. Please login to access this video. Caption In northern Alaska, within the Arctic Circle, the ice regimes of shallow lakes were documented using 79 radar images from the ERS-1 and -2 satellites. How the radar signals bounced back to the sensor indicated 'floating ice' versus 'grounded ice' (fully frozen lake) when radar energy was absorbed into the ground. The data showed that from 1992 to 2011 the lakes in this region experienced a 22% reduction in grounded ice -- the equivalent of ice thinning by 21-38 cm. Credit Planetary Visions, University of Waterloo, Canada, European Space Agency Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.