Research On Remote Sensing Model Retrieval Of Wetland Evapotranspiration

Regional evapotranspiration of wetland is the main component of the wetland water expenditure; it can characterize the vegetation cover of the wetland ecosystem and plant growth. In recent years, intensive human activities cause the emergence of a certain degree of wetland ecosystem degradation. In order to protect the wetland ecosystem and maintain wetland ecological needs of water, the research of wetland regional evapotranspiration become inevitable and it has important ecological protection significance. Evapotranspiration research is still on point-based stage; using remote sensing techniques to the estimate regional evapotranspiration has become a trend. Existing remote sensing models are almost proposed in the arid and semi-arid conditions and not suitable for wetland regional evapotranspiration, so how to use existing remote sensing model on wetland regional evapotranspiration becomes the focus of this studyThis paper takes BaiYangDian Wetlands as an example, and uses two remote sensing models to estimate wetland regional evapotranspiration, based on multitemporal TM remote sensing image data and meteorological data provided by wetland automatic weather station, one model base on surface energy balance equation and the other based on space experience between the and the surface parameters combining with the special land use of wetland. Through the comparison between the measured evapotranspiration data and the model’s output, we find that the model estimation error is very small, so the improved remote sensing models are suitable for wetlands regional evapotranspiration. In remote sensing energy balance model to estimate the wetland regional evapotranspiration process, considering the complexity of the wetland ecosystem, first remote sensing image classification technique is used to achieve land use and vegetation cover classification of wetlands, then select the appropriate remote sensing model according to various features of underlying surface, and make some appropriate parameter adjustments and improvements to meet the needs of remote sensing model, finally the integrated remote sensing of evapotranspiration model is obtained by the combination of the terrain classification. When using the spatial experience the relationship between surface parameters to estimate evapotranspiration, in this paper, scatter plots between vegetation indices and surface temperature is used to interpolate the PT parameters of PT equation fitting for estimation of evapotranspiration in the humid conditions, then calculate evapotranspiration respectively according to the degree of the saturation of the wetland underlying surface, finally the estimation of wetland regional evapotranspiration is completed. This paper focuses on the research of evapotranspiration of water body and aquatic plants in wetland, during the results validation part, through the comparison of the measured evapotranspiration data and model output results, the effectiveness of the remote sensing model for wetland evapotranspiration is proved.