Evapotranspiration analysis based on topography algorithm in the Yellow River Delta

A remote sensing regional evapotranspiration (ET) model was built on the basis of topography correction (slope, aspect and elevation), herein. A variety of satellite data which have visible, near-infrared and thermal infrared remote sensing data can be used by this improved model. Combined with conventional ground meteorological information, it can estimate regional distribution of ET under different climate and terrain conditions, expanding the scope of application. Taking into account the terrain factors, we modified the algorithm of SEBAL model. Results showed that, the modified inversion method of evapotranspiration can better reflect actual evapotranspiration condition. Evapotranspiration changes were consistent with land use types. This research indicates that application of medium or high resolution satellite data to calculate regional ET under undulating landform should consider the impact of terrain. It improves the accuracy of ET estimates and has important reference value for the work of the regional water balance and regional agricultural climate research.