Estimation of evapotranspiration based on remote sensing in Heihe River Basin

<span class="hit">Regional</span> <span class="hit">evapotranspiration</span> (ET) is an important component in water cycle and energy balance. The research <span class="hit">on</span> <span class="hit">regional</span> <span class="hit">evapotranspiration</span> is very important to further our understanding <span class="hit">of</span> the global climate change, land surface atmosphere interaction, water cycle and ecological study. However, traditional site observation is only representative <span class="hit">of</span> the local site scale, which can not reflect the real <span class="hit">regional</span> conditions. Remote sensing provides a promising way to retrieve <span class="hit">regional</span> <span class="hit">evapotranspiration</span>. Heihe River Basin is the second largest inland river basin in northwest <span class="hit">of</span> China, water shortage has become a crucial problem to <span class="hit">regional</span> ecological, environmental, economic and other related areas. The research <span class="hit">on</span> <span class="hit">regional</span> <span class="hit">evapotranspiration</span> is in an urgent need in this area. SEBS model, a physically <span class="hit">based</span> model, was selected to retrieve <span class="hit">regional</span> <span class="hit">evapotranspiration</span>. Combined with MODIS products and site observations, <span class="hit">evapotranspiration</span> in typical days were <span class="hit">estimated</span> with SEBS model. The instantaneous results were validated with flux observation data from Yingke station. In most days SEBS model have good <span class="hit">estimation</span> <span class="hit">of</span> surface fluxes, the difference between observations and <span class="hit">estimation</span> is limited in 50W/m^{<font size="2">2</font>}. For longer time ET <span class="hit">estimation</span>, reference <span class="hit">evapotranspiration</span> fraction was selected to scale instantaneous measurements to daily and motherly <span class="hit">evapotranspiration</span>. Adjusted pan observations were used to validate the scaled daily results, the results indicate reference <span class="hit">evapotranspiration</span> fraction <span class="hit">based</span> method have good quality to scale daily ET. Moreover, clear spatial patterns <span class="hit">of</span> ET were found in Heihe River Basin. This spatial pattern is closely correlated with land use/land cover and water uses in Heihe River Basin