HR: 1340h
AN: G13B-0809    [Abstracts]
TI: Assessing the Ability of Laser Altimeter Return Waveforms To Detect Surface Topographic Change
AU: * Hofton, M A
EM: mhofton@geog.umd.edu
AF: University of Maryland, Department of Geography, College Park, MD 20742 United States
AU: Blair, J B
EM: james.b.blair@nasa.gov
AF: NASA Goddard Space Flight Center, Laser Remote Sensing Branch, Greenbelt, MD 20771 United States
AU: Rabine, D L
EM: david@ltpmail.gsfc.nasa.gov
AF: Space Science Applications Inc., NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Padden, P
EM: ppadden@cornfed.gsfc.nasa.gov
AF: Space Science Applications Inc., NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AB: The capability of medium/large footprint (10 m or greater) full-waveform laser altimeters to penetrate beneath dense vegetation to directly measure sub-canopy topography provides a unique capability for sensing topographic change in the presence of vegetation. In this study, we assess the ability of geolocated laser altimeter return waveforms instead of individual elevation measurements to measure vertical elevation change. The method we use (dubbed the return pulse correlation method) maximizes the shape similarity of near-coincident, vertically-geolocated laser return waveforms from two observation epochs as they are vertically-shifted relative to each other. Using waveform data collected by NASA's Laser Vegetation Imaging Sensor (LVIS) we assess the inherent precision of elevation change measurements derived using the return pulse correlation method. Data collected in 1999, 2003 and 2004 are compared using the pulse correlation method and by simple differencing of coincident elevation measurements. Data collected under "bare earth" conditions as well as in the presence of dense, growing vegetation are utilized, demonstrating the usefulness of this technique for complementing and extending earth surface dynamics measurements made using other remote sensing techniques.
DE: 5464 Remote sensing
DE: 1206 Crustal movements--interplate (8155)
DE: 1294 Instruments and techniques
DE: 1640 Remote sensing
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting