HR: 0800h
AN: B11A-0124    [Abstracts]
TI: A Comparison of Landsat TM and ASTER for Equivalent Water Thickness Derivation in a Ponderosa Pine Ecosystem
AU: * Toomey, M
EM: Michael.Toomey@sdsmt.edu
AF: South Dakota School of Mines and Technology, Institute of Atmospheric Sciences 501 East Saint Joseph Street, Rapid City, SD 57701 United States
AU: Vierling, L
EM: Lee.Vierling@sdsmt.edu
AF: South Dakota School of Mines and Technology, Institute of Atmospheric Sciences 501 East Saint Joseph Street, Rapid City, SD 57701 United States
AB: Landsat TM and ASTER satellite data can be used to make physically-based estimates of equivalent water thickness (EWT) in a Pinus ponderosa ecosystem. EWT is a measure of ecosystem water status and is an important parameter for studying ecosystem dynamics, fire potential, and biological responses to climate change. Near infrared (NIR) and shortwave infrared (SWIR) reflectances were simulated using the LIBERTY and GeoSAIL leaf and canopy reflectance models; the results were used to calculate a NIR/SWIR ratio and a normalized NIR/SWIR index. Index-EWT relationships were modeled and inverted for EWT derivation. Landsat and ASTER were used to make reasonably accurate estimates of EWT ($\pm$ 17.3% and 19.4% mean error, respectively); TM band 5 and ASTER band 4 produced the best results. Exclusion of plots with dense understory vegetation reduced point scatter substantially, especially with Landsat (r2 = 0.847, $\pm$13%), indicating that this method can provide robust EWT quantification in homogeneous conifer ecosystems.
DE: 1694 Instruments and techniques
DE: 1833 Hydroclimatology
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting