Estimation of evapotranspiration in Yellow River Delta wetland based on two-source energy balance (TSEB) model

摘要

Evapotranspiration(ET) as the main form of exchanges between the water and heat to the soil-atmosphere of the wetland ecosystem greatly affects the water thermal equilibrium. Estimation of the evaporation quantity reasonably and accurately is of great significance to study hydrologic recycle, energy balance and scientific management of the wetland ecosystem. Wetland in Yellow River Delta (YRD), which is the most integrated, broadest, youngest wetland ecological system in warm temperate zone of the earth, is not only sensitive to climate change, but also fragile to the environment change. Remote sensing technique is used to estimate ET in YRD in our case study. Coupling the model of Surface Energy Balance Algorithm for Land (SEBAL) and Two-Source Energy Balance (TSEB), SEBAL is used to calculate land surface characteristic parameters and flux, and TSEB is used to calculate vegetation transpiration, soil evaporation and total ET separately of YRD by Considering the inner structure of the surface layer which can be divided into two sub layers representing soil and vegetation. Then the spatial distribution of the daily ET is analyzed and the characteristics of ET with different features, especially with the typical vegetation of reed marshes and meadows, are also analyzed to help realize the wetland conditions. The results illuminated that daily ET estimated is reasonable and the method can be used for the accurate estimation of ET in YRD.