Estimation Of Evapotranspiration In Wheat Area Of Henan Province Based On SEBS Model

Evapotranspiration is the process of returning to the atmosphere from the gaseous or solid state to the water-vapor after the precipitation reaches the ground.It is not only an important part of the hydrological cycle process,but also an important link between the connection energy and the water balance.Quantitative acquisition of regional surface evapotranspiration is an important part of climate change,agricultural production,hydrology and ecology,and water resources management.China is water resources are extremely uneven distribution in developing countries and a long-established agricultural country.Accurate estimation of evapotranspiration contributes to the rational allocation of water resources in China,the improvement of water use efficiency,and the acceleration of agricultural modernization.For all levels of government and region will provide a scientific basis for precision agriculture production decision,the understanding of regional and global climate change is of great significance.This study is based on the SEBS model developed by the Chinese-Dutch Su based on the surface energy balance equation.The winter wheat growing area in Henan Province is used as the research area.The MODIS/VIIRS remote sensing data is used as the remote sensing data source,and the DEM elevation data and meteorological stations are used as auxiliary data.Based on the platform of ArcGIS/ILWIS(Integrated Land and Water Information System)/ENVI(The Environment for Visualizing Images),the multi-source and multi-scale remote sensing information is integrated to invert the high-time space of the winter wheat planting area in Henan Province from the 65 th to the 144 th.The evapotranspiration data under resolution was used to analyze the temporal and spatial changes of evapotranspiration,surface temperature,net radiation flux and latent heat flux in winter wheat planting areas in Henan Province.The accuracy of the inversion was verified by using the measured evapotranspiration data.At the same time,the sensitivity between the model input parameters and the evapotranspiration inversion results is analyzed to reduce the workload.Through analysis and research,the following conclusions are obtained:(1)Based on the SEBS model,this paper selects 61/79/107/108/143 5th of 2018 as the experimental data,and using the MODIS remote sensing data and separately MODIS remote sensing data fusion single variable in both cases.inversion evaporation verifies the accuracy of the results of inversion,found that after fusion of MODIS remote sensing data after the single variable precision inversion evaporation decreases,the analysis found that this should be VIIRS remote sensing data of infrared and near infrared band relative to the resolution of MODIS remote sensing data down due to this reason.(2)The evapotranspiration of winter wheat planting area in Henan Province showed significant changes with the change of seasonal temperature.From the beginning of March to the end of May,the overall trend showed a rising peak;In terms of space,evapotranspiration from northwest to southeast showed an increasing trend,which was more consistent with the spatial distribution of NDVI.Its maximum wave peak was on the 129 th day(May 9),and its pixel mean value had exceeded 4 /.The results of precision verification show that the evapotranspiration error of inversion is between 0.013 and 0.366 mm/day,which is within a reasonable range.(3)By analyzing the spatial-temporal variation characteristics of surface parameters and fluxes of the model,it is found that the trend of rise or fall between surface temperature and air temperature is consistent,and the correlation coefficient between them is as high as 0.9137.The analysis shows that the opposite trend of the increase and decrease trend is the surface net radiation and surface albedo,sensible heat flux and latent heat flux.At the same time,when the value of latent heat flux is at the peak and valley,the value of sensible heat flux is in the trough.(4)In this paper,based on SPSS software,the sensitivity analysis of standardized land surface physical parameters,meteorological parameters and evapotranspiration is carried out,and the analysis shows that the parameters based on remote sensing data and meteorological data inversion have positive and negative correlation with evapotranspiration.At the same time,through the method of principal component analysis,three principal components are extracted from many parameters,and three principal components are used to represent the information carried by the original parameters,so as to achieve the purpose of dimensionality reduction.