HR: 1330h
AN: H23B-12    [Abstracts]
TI: Reducing Uncertainties in Estimates of Evapotranspiration Using only Remotely Sensed Data, Three Gorges Region of China
AU: * Runkle, B R
EM: brrunkle@ce.berkeley.edu
AF: Civil and Environmental Engineering, University of California-Berkeley, Berkeley, CA 94720 United States
AU: Liang, X
EM: liang@ce.berkeley.edu
AF: Civil and Environmental Engineering, University of California-Berkeley, Berkeley, CA 94720 United States
AB: Accurate water and energy budgets depend on high quality estimates of local and regional evapotranspiration. Ground measurements are rare for many under-gauged regions of the world, so the use of remote sensing data to determine these estimates is especially appealing. Remote sensing offers greater spatial coverage (i.e. global) than traditional measures, but has its limitations (e.g., may have less-frequent temporal sampling, and the length of such datasets is limited to the launch of appropriate satellites). Additionally, there are uncertainties associated with methods for deriving evapotranspiration estimates. In this study, we apply the method by Jiang and Islam (2001) of combining the Priestley-Taylor equation and NDVI-Surface Temperature relationship to estimate the evapotranspiration (ET) for a large area using remote sensing information (e.g., MODIS data). ET estimates from this approach are compared to the potential evapotranspiration data measured by two methods (small and large pans) on the ground. Evaluations of the validity of the method by Jiang and Islam and other relevant methods for the study region will be provided, with an effort to reduce methodological uncertainties. Estimates of evaporation at sixteen-day intervals and 1 km resolution are determined for over one year. Our estimates are unique by avoiding the use of flux towers, and can provide accurate predictions of evapotranspiration using only remotely sensed data. The large area to be studied is in the Three Gorges Region of China, a region undergoing rapid environmental, land-use, and hydrological change. As the Three Gorges Dam undergoes filling, accurate assessments of the region's hydrology have important implications for its water quality, public health, and economy.
DE: 0933 Remote sensing
DE: 1818 Evapotranspiration
DE: 1857 Reservoirs (surface)
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2005 Joint Assembly