Estimaton of evapotranspiration in catchment based on distributed watershed hydrological model

The distributed hydrological model including dual-source evapotranspiration moduleand runoff-yield module based on grid excess saturation scheme was established for simulating the evapotranspiration process of temporal and spatial variance was estimated in Dianzi basin, headwater region of Laoha River. The modeling result confirmed that the dual-source model could effectively simulate the actual evapotranspiration process in catchment scale and well support the distributed hydrological modeling rather than the potential evapotranspiration estimated by the pan measurement. The temporal variance of nterception evaporation, plant transpiration and evapotranspiration for different vegetations was similar, with the peak value in summer. Tall vegetation transpiration and proportion of productive evaporation was significantly higher than that of low vegetation. However, the temporal variance of evapotranspiration for soils covered for different vegetations was heterogeneous; the peak value of tall vegetations was in May and the peak value of short vegetations was in June or July.