Estimation Of Temporal And Spatial Changes Of Evapotranspiration In The Ebinur Lake Basin Based On SEBS Model

In the process of natural water transport,the evapotranspiration of water plays a key role,which consists of evaporation and transpiration.Evapotranspiration is a process in which water is converted from a liquid state to a gaseous state.In this process,energy conversion is accompanied by one of the important ways of energy conversion and transmission between the Earth's surface and the atmosphere and the atmosphere.Clouds,fog,precipitation,and The occurrence of other weather phenomena has an important role,even affecting regional and even global climate changes.The actual evaporation and evapotranspiration of water on the ground is of great significance in many fields,such as climatology,hydrology,ecology,etc.,especially in areas with poor natural conditions and lack of moisture in arid and semi-arid regions.Quantitative estimates can clarify the water consumption in arid and semi-arid areas,and the ecological water requirements needed for crops and maintaining ecological environment.Deep in the Ebinur Lake Basin,Eurasia is inland,with arid and dry climate,strong winds,huge evaporation,and a large number of sunshine hours.It belongs to the typical temperate continental climate.The problem of eco environment in the Ebinur Lake Basin is mainly due to the depletion of water resources.From 50th to80th centuries in the last century,with the social development and economic prosperity of our country,the number of people in the river basin showed an explosion increase,the area of farmland increased,the increase of farmland resulted in the increase of the total amount of irrigation water,the consumption of rivers and groundwater reduced the water quantity of the lake,resulting in the decrease of the lake area and the change of the total amount of the lake.The consequences of the reduction and the reduction of the lake surface are mainly due to the degradation of natural conditions and ecosystems,as well as a series of ecological and environmental problems,such as the serious degradation of the lake ecosystem,the decrease of biodiversity,the increase of the number of dust and dust storms,the degradation and desertification of the soil.The key to the mitigation and planning of ecological crisis and environmental problems in the Ebinur Lake area is to improve the water use rate and allocate the limited water resources reasonably,and the estimation of the evapotranspiration of the river basin can provide an important reference.In the area of evapotranspiration estimation,the traditional monitoring method is difficult to realize,but in recent years,the development of remote sensing technology provides an opportunity.Remote sensing method mainly uses satellite remote sensing technology to obtain the remote sensing image of the target area,and then calculates the evapotranspiration value of the target area by various models.In this paper,based on the SEBS model,the surface energy balance theory and the MODIS remote sensing image products,the meteorological factors of the research area are analyzed,and the MODIS data are retrieved by ILWIS,ENVI,ARCGIS and other software.Finally,the spatial distribution map of 120 scenery daily average evapotranspiration from 2007 to 2016 in the Ebinur Lake Basin is obtained.The time variation and spatial distribution characteristics of the evapotranspiration,the correlation between the surface parameters and the meteorological factors and the evapotranspiration of different land cover types,and the characteristics of the evapotranspiration of different types of land cover are analyzed.Finally,the applicability of the model is tested by the comparison and analysis of the field measurement data of the eddy correlator and the SEBS model.The main conclusions of this study are as follows:?1?the evapotranspiration of the Ebinur Lake study area changed in time series.From 2007 to 2016,the daily average evapotranspiration in each cycle was a single peak distribution throughout the year,which gradually increased from January to the middle of July,and gradually decreased from the middle of July to the end of December,and the evapotranspiration was changed in the year.The trend of chemical transformation is a normal distribution with time.The evapotranspiration characteristics of the evapotranspiration have a significant difference in the evapotranspiration from 2007 to 2009,2010 to 2014,and from 2015 to 2016.In the comparison of the same month's evapotranspiration,July and October showed an upward trend in the years of change,and the rest of the month showed a trend of constant or decrease in the annual change.The variation of the evapotranspiration in the Ebinur Lake Basin is closely related to the change of the meteorological elements in the same time series.The correlation from high to low is:air,atmospheric pressure,sunshine time and wind speed.In addition to the negative correlation,the air temperature,sunshine time and wind speed are in positive phase with the evapotranspiration.Close.?2?in space distribution,the evapotranspiration of the basin range from January to March was basically at the edge of the ridge.The maximum evapotranspiration in March was only 1.75 mm?d^-1,and the average value of the basin was 0.54 mm?d^-1.The average evapotranspiration of the whole basin was 2.62 mm?d^-1,2.33 mm?d^-1,2.68mm?d^-1,5.29 mm?d^-1 and 3.7 mm?d^-1,respectively 1.26 mm?d^-11 in April to September.The areas of strong evapotranspiration are mainly in the ridge,hillside and Ebinur Lake area of the west,South and North.In June^September,the evapotranspiration of the farmland is generally high.The evapotranspiration near the grassland and the river in the mountains and in the front of the mountain is also maintained at a high state,and the areas with the lowest evapotranspiration are generally spread throughout the area.In the plain and desert areas,the average evapotranspiration of the whole basin was 0.65 mm?d^-1 0.46 mm?d^-1 and 0.32 mm?d^-1 in October,and the evapotranspiration of the whole basin was very small and mainly distributed at the ridge of the border.?3?The species of land cover in the Ebinur Lake basin can be divided into six types:arbor forest,shrub,grassland,arable land,water and"other"types.The high and low distribution of the evapotranspiration and the type of land cover in the basin has a higher unity.In May^September,the evapotranspiration in the fields except the farmland,the front of the mountain,and the river near the river was compared.The evapotranspiration of other regions is lower than that of other regions.Six the average daily evapotranspiration of the cultivated area is:water>cultivated land>grassland>arbor woodland>other>shrub land.The evapotranspiration characteristics of different land cover were different,the peak of tree forest appeared at 1.20 mm?d^-1 and 6.80 mm?d^-1 respectively.The peak of shrub forest appeared respectively in 3.5 mm?d^-1 and 6 mm?d^-1.The herbage land appeared respectively in 4mm?d^-1 and 6.80 mm?d^-1.The peak value of cultivated land and water was 6.60 mm?d^-1,6.60 mm?d^-1,7 mm?d^-1,respectively 20 mm?d^-1.?4?the results of SEBS model inversion are verified by the eddy correlation method.The standard error between the estimated value of the SEBS model and the observed value of the vorticity correlation system is less than 10%,the root mean square error is 0.46,the error is between the allowable range,and the SEBS model is of high application value in the arid area.