Monitoring Ice Sheets, Glaciers, and Sea Level
For the bottom (October 1994) image, the temperatures were colder, and the corresponding change in snow and ice conditions is apparent. The interior of the ice field is brighter, indicating the snow is dryer. A portion of the boundary of the outlet glacier at the top left-center of the images has advanced approximately 600 meters (1,970 feet) in the 5½ months. Because of the persistent cloud cover this observation was possible only by using orbiting, remote imaging radar (in this case, SIR-C/X-SAR, flown aboard the Space Shuttle).
LightSAR's Potential Contribution:
Ice sheets and glaciers contain nearly 80% of the world's fresh water and are the primary source of any future rise in sea level. While the general retreat of mountain glaciers globally is believed responsible for one-quarter to one-third of the current 2 millimeter/year rise in sea level, the majority of the remainder is most likely the result of as yet undiscovered imbalances in the large polar ice sheets.
LightSAR will be able to measure glacier and ice sheet velocities and topography using special interferometric techniques. LightSAR will also be able to monitor critical margins of ice sheets and glaciers. Its planned orbit will allow it to view most of Antarctica, where over 90% of Earth's ice reservoir resides.
By regularly imaging the Greenland and Antarctic ice sheets, LightSAR can help to document the short- term evolution of the ice sheets.