Evaluation of Geoscience Laser Altimeter System (glas) Waveforms for Vegetated Landscapes Using Airborne Laser Altimeter Scanning Data

The Geoscience Laser Altimeter System aboard NASA’s Ice, Cloud and land Elevation Satellite will record the height distribution of laser energy reflected from surfaces within 70 m diameter footprints. For land surfaces, post-processing of this waveform data will be used to estimate the within-footprint mean elevation and surface relief due to ground slope and roughness, vegetation cover, buildings and other structures. A methodology is described for validating the derived surface properties for vegetated and urbanized landscapes using a GLAS waveform simulator applied to high-resolution, airborne, scanning laser altimeter data being acquired by the Puget Sound Lidar Consortium (PSLC) in northwestern Washington state. The GLAS waveform simulator is being modified to operate on 3dimensional representations of topography and vegetation cover with the incorporation of digital elevation models derived from the airborne laser data and representations of the spatial distribution of surface reflectance, the transmitted laser energy measured on a perpulse basis by the GLAS instrument, and detector's field-of-view responsivity. The attributes of the PSLC airborne laser mapping data are also described.