Sea-Ice Freeboard Retrieval Using Digital Photon-Counting Laser Altimetry

• Main Authors: Farrell, Sinead L., Connor, Laurence N., Walsh, Kaitlin M., Brunt, Kelly M., Ruth, Julia M., Kuhn, John M.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2015
• Subjects: Geosciences (General); Earth Resources and Remote Sensing; Arctic; Greenland; Mabel; Greenland Sea; ice pack; Sea ice
• Online Access: http://hdl.handle.net/2060/20150004436

Airborne and spaceborne altimeters provide measurements of sea-ice elevation, from which sea-ice freeboard and thickness may be derived. Observations of the Arctic ice pack by satellite altimeters indicate a significant decline in ice thickness, and volume, over the last decade. NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) is a next-generation laser altimeter designed to continue key sea-ice observations through the end of this decade. An airborne simulator for ICESat-2, the Multiple Altimeter Beam Experimental Lidar (MABEL), has been deployed to gather pre-launch data for mission development. We present an analysis of MABEL data gathered over sea ice in the Greenland Sea and assess the capabilities of photon-counting techniques for sea-ice freeboard retrieval. We compare freeboard estimates in the marginal ice zone derived from MABEL photon-counting data with coincident data collected by a conventional airborne laser altimeter. We find that freeboard estimates agree to within 0.03m in the areas where sea-ice floes were interspersed with wide leads, and to within 0.07m elsewhere. MABEL data may also be used to infer sea-ice thickness, and when compared with coincident but independent ice thickness estimates, MABEL ice thicknesses agreed to within 0.65m or better.