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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Restoration Ecology
USING REMOTE SENSING TO ESTIMATE EVAPOTRANSPIRATION ALONG THE MIDDLE RIO GRANDE – THE VEGETATIVE INDEX METHOD.
D.E. McDonnell, C.N. Dahm, J.R. Cleverly, and J.R. Thibault. Department of Biology, University of New Mexico, Albuquerque, NM 87131
The goal of this research was to determine whether a remotely sensed vegetation indices related to Leaf Area Index (LAI) could be used to calculate evapotranspiration (ET) along the Middle Rio Grande riparian corridor. Both ground-based and remote sensing techniques were used to estimate riparian zone ET at the plot scale by combining state-of-the-art micrometeorological measurements with ground based and satellite based determination of LAI. Data collected at micrometeorological towers at four sites formed the basis for calculating ET using the eddy covariance method. Resulting ET estimates were strongly correlated to field based measurements of LAI using LICOR LAI meters taken at the four tower sites and eight additional study sites. Using the relationship between LAI and ET, ET was calculated for all twelve study sites. The relationship between ET calculated at the 12 sites was then compared to remotely sensed vegetation indices using Landsat 7 Enhanced Thematic Mapper imagery. The relationships found between remote sensing vegetation indices and ET were encouraging, although they were different between salt cedar and cottonwood stands. The results showed that a remotely sensed vegetation index could be used to determine ET along the riparian corridor provided a good vegetation classification was available.
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