Characterizing Ice Sheet Surface Topography and Structure Using High-Altitude Waveform Airborne Laser Altimetry

Surface topographic information of ice surfaces is important for a wide range of applications including mass balance investigations and dynamical modeling. Airborne LIght Detection And Ranging (lidar) uses laser ranging to map surface topography with high precision and accuracy. In October-November 2010, NASA's Land, Vegetation and Ice Sensor (LVIS) system imaged areas of Antarctica as part of NASA's Operation IceBridge (OIB) on board the DC-8 aircraft. The LVIS is an airborne, medium-footprint (~25 m diameter), wide swath (~2 km) full waveform-recording, scanning lidar system that has been used extensively for mapping surface structure for various investigations. 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 within each footprint in the data swath. During the 2009 Antarctica deployment, LVIS Lidar data were collected over the Antarctic Peninsula, Pine Island Glacier and along a ~1100 km-long transect around 86S from flight altitudes of ~35,000' to ~39,000', and complemented and enhanced the low-altitude radar and laser datasets also collected during the mission. We examine the LVIS lidar imaging data sets, in particular that collected in the Antarctic Peninsula where an 11 hour flight enabled the complete mapping of a ~250 km by ~30 km area centered on the Crane Glacier. A precision and accuracy assessment of the high-resolution digital topographic data products is presented, as well as comparisons of the data to existing elevation maps from ASTER and SPOT5 to quantify surface changes within several mapped glacier systems. This mapping demonstrates the unprecedented spatial coverage and accuracy of the high-altitude lidar data collected during OIB.