ESTIMATION OF EVAPOTRANSIPIRATION OF GRASSLAND AND CROPLAND ECOSYSTEMS IN ARID REGION BASED ON MODIS SATELLITE DATA AND PENMAN- MONTEITH EQUATION

摘要

Remotely sensed data have long been seen as the best way to determine spatially distributed evapotranspiration (ET) fluxes owing to their spatial and temporal continuity. A simple biophysical model by using remotely sensed leaf area index data and the Penman-Monteith (PM) equation was introduced to calculate daily ET of grassland and farmland in the middle and upper reaches of Heihe River Basin. The modelled daily ET agrees well with measurements and the R2 is over 0.80. This study confirmed that the PM equation with MODIS LAI can provide reliable estimates of ET at daily time scales and with different ecosystems in arid and cold regions.