Characterizing and Mapping Ice Sheet Surface Topography Using a Medium-Footprint, Multi- Beam, Waveform-Recording Lidar, * Hofton, M A mhofton@umd.edu, Department of Geography, University of Maryland, College Park, MD 20742, United States, Blair, J B, James.B.Blair@nasa.gov, Code 694, NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States, Rabine, D L, David.L.Rabine@nasa.gov, Science Systems and Applications Inc., 10210 Greenbelt Road, Lanham, MD 20706, United States, Luthcke, S B, Scott.B.Luthcke@nasa.gov, Code 698, NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States Abstract: Lidar surveys of the Greenland ice sheet have been used to study mass-balance changes since the early 1990's. Sensors include NASA's ATM system (e.g., Krabill et al., 2000), and the ICESat (Schutz et al., 2002), a large- footprint, spaceborne system launched in 2003 for monitoring long-term trends in ice mass balance. To complement these data sets and prepare for the next-generation of spaceborne measurements, the Laser Vegetation Imaging Sensor (LVIS) was flown onboard the NASA P-3 aircraft over Greenland in September 2007. LVIS is an airborne, medium- footprint (25m diameter), full waveform-recording, airborne, scanning lidar system that has been used extensively for mapping forest structure, habitat, carbon and natural hazards. The system digitally records the shape of the returning laser echo, or waveform, after its interaction with the various reflecting surfaces of the earth, providing a true 3-dimensional record of the surface structure. Data collected included ground elevation and vertical extent measurements for each laser footprint, as well as the vertical distribution of intercepted surfaces (the return waveform) from which surface slope, roughness and other metrics can be extracted. During the mission, data were collected along ICESat repeat ground-track “corridors” that encompass a variety of terrain types (e.g., inland ice, crevasses, ponds, sastrugi, ice/rock margins, and bare earth), over sea- ice in northern Greenland, and at Jakobshavn Isbrae, a fast-flowing outlet glacier where discharge rates have increased in recent years. Data from this mission will be used to assess the ability of 25m-footprint, waveform lidar to precisely and accurately characterize and monitor the surface of the Greenland ice sheet and its margins. The data will also be used to assess the effects of across-track slope corrections currently being used on the ICESat data. The study will highlight the complimentary measurement science that can be achieved using a multi-beam, 25m footprint, contiguous beam laser altimeter such as the one proposed for inclusion in the DESDynI mission, especially in the high-slope, highly dynamic areas of Greenland. Citation: Cite abstracts as Author(s) (2007), Title, Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract xxxxx-xx Your query was: “G53A-04”