Study On Evapotranspiration Based On SEBS Model In Handan

Evapotranspiration,the sum of water lost to the atmosphere form the surface,is key input in hydrologic cycle and water resources management.The inversion of evapotranspiration is important to Handan City,which is a water shortage city.Based on the theory of SEBS model,combined with the MODIS product data,DEM data and Chinese meteorological data network's meteorological observation data,got 90 daily evapotranspiration inversion results in Handan,from eighty-first to 353 rd days a year in 2012-2016(16 days for each time interval).The analysis on the time-variation between evapotranspiration and surface temperature,surface albedo,NDVI in conducted,and the spatial distribution law is also studied from March to December 2016.What's more,correlation analysis between the evapotranspiration inversion results and the main model input parameters is carried out,and 4 principal components are extracted from the input parameters of the model to achieve the dimensionality reduction effect.Less research on scale expansion from daily evapotranspiration to annual accumulation,a trapezoid and piecewise function method is proposed to estimate the annual cumulative evapotranspiration on the basis of integral thought.The estimation results show that the maximum yearly cumulative evapotranspiration value is in 2012 reached more than 800 mm,the minimum value is about 640 mm in 2015,and,the overall level of 5 years is declining.Cause of the absence of ground monitoring data for parameters such as evapotranspiration or surface flux in the Handan region,the comparison and verification of the solar radiation monitoring data from the meteorological station data and the inversion of the solar radiation are carried out in the experiment.The correlation coefficient of the two is up to 0.83,which ensures the reliability of the experimental results.