Temporal and spatial variation characteristics of surface evapotranspiration and drought in southwest China in recent 20 years
The data of temperature,vapor pressure of 161 meteorological stations in 5 provinces in Southwest China from 1996 to 2015 and MODIS product data were used to fit the surface evapotranspiration in southwest China,based on the improved hybrid linear dual source remote sensing evapotranspiration model. The evapotranspiration drought index (EDI) was defined to analyze the temporal and spatial variation characteristics of drought in the area. The results show that:in the past 20 years,the actual e-vapotranspiration in southwest China has increased obviously,and it is larger in spring and summer,accounting for 62.3% of the annual evapotranspiration. In spring,the actual evapotranspiration descends from the southeast to northwest, and it is larger in southern Guangxi and Yunnan. While, in summer, it shows a decreasing trend from east to west, from Guangxi, Guizhou, Chongqing to Yunnan and Sichuan. In autumn and winter, it decreases from south to north. Potential evapotranspiration also shows an increasing trend and the seasonal variation trends are coincident with the actual evapotranspiration. It also accounted for 60.6% of the total annual evapotranspiration in Spring and summer. However,compared to the actual evapotranspiration in view of spatial distribution,the variation of potential evapotranspiration has certain rules. In spring,autumn and winter,it shows obvi-ous decreasing trend from south to north with a latitudinal differentiation distribution, but in summer, it decreases from east to west with a longitudinal differentiation distribution. The interannual EDI shows a fluctuating and obviously decreasing trend in the past 20 years,but the average EDI of each year is greater than 0.5,indicating that the overall degree of drought is relatively seri-ous.
Southwest Chinasurface evapotranspirationevapotranspiration drought index(EDI)temporal and spatial varia-tion
国家科技期刊平台
NSTL
万方数据
维普
