Credit: Image courtesy of Fricker, Helen Amanda; Ted Scambos; Robert Bindschadler; Laurie Padman: "An Active Subglacial Water System in West Antarctica Mapped from Space." Science 315, no. 5818 (2007): 1544-1548.
(Top left) ICESat 91-day tracks across newly discovered subglacial Lake Engelhardt in West Antarctica. Tracks are color-coded by elevation changes between October 2003 and November 2005. White asterisks locate tide-induced ice-flexure limits for the grounding line derived from ICESat repeat-track analysis. (Top right/bottom left) Repeat ICESat profiles along two tracks across the lake (see top left panel for locations). Track 206 was an almost exact repeat of an 8-day track. (Bottom right) ICESat elevations against time at three orbit crossovers in the center of the lake including the 8-day data at crossover 1 in February/March 2003.