HR: 16:45h
AN: C34A-04    [Abstracts]
TI: Ocean height, waves, and reflectivity from ICESat
AU: * Urban, T J
EM: urban@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker, Suite 200, Austin, TX 78759 United States
AU: Schutz, B E
EM: schutz@csr.utexas.edu
AF: Center for Space Research, University of Texas at Austin, 3925 W. Braker, Suite 200, Austin, TX 78759 United States
AB: Sea level height measurements from ICESat display global characteristics comparable to radar altimeters such as TOPEX/Poseidon. Daily averages of sea level height have a precision at the centimeter level, equivalent to similar comparisons using radar altimetry. However, a relative bias exists between TOPEX and ICESat elevations, possibly due to an unaccounted-for laser sea state bias. Radar altimetry elevations can be corrected for a sea state bias effect by using an empirical correction that is a function of radar-waveform-derived significant wave height (SWH) and wind speed. In lieu of SWH and wind speed, we examine ICESat's high-frequency elevation noise (RMS) and laser pulse reflectivity. A 1-Hz average of ICESat elevations encompasses a similar collection of sea states as does the much larger 1-Hz radar footprint, thereby sampling ocean variability caused by waves, winds, and swell. This variability is reflected in the RMS of 40-Hz ICESat data about a 1-Hz mean. Surface characteristics also affect the ICESat reflectivity parameter, a ratio of received and transmitted energies. Similarities and differences between ICESat laser and radar ocean height and variability parameters are shown. We note that ICESat data from different laser campaigns and product releases can display distinctly different characteristics. A preliminary sea state bias model is generated for ICESat using only ICESat-derived parameters.
DE: 1222 Ocean monitoring with geodetic techniques (1225, 1641, 3010, 4532, 4556, 4560, 6959)
DE: 4260 Ocean data assimilation and reanalysis (3225)
DE: 4540 Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754)
DE: 4556 Sea level: variations and mean (1222, 1225, 1641)
DE: 4560 Surface waves and tides (1222)
SC: Cryosphere [C]
MN: Fall Meeting 2005