HR: 1330h
AN: H42A-1066    [PDF]
TI: Characterization of land surface energy fluxes at the Salar de Atacama, Northern Chile using ASTER image classification
AU: * Kampf, S K
EM: stephk@u.washington.edu
AF: Department of Civil and Environmental Engineering, University of Washington Box 352700, Seattle, WA 98195
AU: Tyler, S W
EM: tylers@unr.edu
AF: Graduate Program of Hydrologic Sciences, University of Nevada, Reno MS 175, Reno, NV 89557
AB: Models of land surface energy fluxes often use remotely sensed data to derive surface temperature, albedo, and emissivity, important parameters in energy budget calculations. The ability to determine the spatial distribution of these parameters can lead to improved estimations of the spatial variability of land surface energy fluxes. However, other parameters used in energy flux calculations such as aerodynamic resistance are not directly linked to quantities commonly derived from remotely sensed data. If images can be accurately classified into separate land cover types, empirically determined values of unknown parameters can then be assigned separately to each land cover classification. This study examines several techniques of determining the spatial distribution of land surface energy fluxes at the Salar de Atacama, a large playa in northern Chile. Fluxes are calculated using Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) Level 2 surface kinetic temperature, surface emissivity, and surface reflectance data in conjunction with ground-based meteorological measurements. Energy fluxes are calculated initially by applying a single value of aerodynamic resistance to the entire image area. Subsequently, the ASTER scene is classified into distinct land cover types, and land surface roughness is characterized using the ratio of ASTER band 3N (nadir-viewing) to band 3B (back-viewing). Separate values of aerodynamic resistance are then assigned to each land cover type, and energy fluxes over the entire Salar de Atacama are calculated using these spatially distributed aerodynamic resistance values. Results of both energy flux calculation techniques are evaluated at several sites on the playa using ground-based energy flux measurements.
DE: 1818 Evapotranspiration
DE: 1878 Water/energy interactions
DE: 3322 Land/atmosphere interactions
DE: 3359 Radiative processes
DE: 3360 Remote sensing
SC: Hydrology [H]
MN: 2003 Fall Meeting