西南喀斯特地区参考蒸散发时空变化及归因研究OA

Understanding the spatiotemporal variation and driving mechanisms of reference evapotranspi-ration(ET0)in the southwest karst region is crucial for regional water resources management.Based on meteorological station observations and digital elevation model(DEM)data,we employed multiple meth-ods to investigate the spatiotemporal characteristics of ET0 and its dominant driving factors during 1980-2019.These methods include the Penman-Monteith(PM)model,trend analysis,partial correlation a-nalysis,relative contribution analysis,structural equation modeling,and random forest.The results show that the estimated ET0 exhibits strong agreement with the CHELSA product,with a correlation coefficient of 0.854 7.ET0 shows an overall increasing trend during the study period,with multi-year mean values ranging from 611.14 to 1 378.16 mm and a regional average of 1 007.39 mm.It increases at a rate of 0.68 mm/a,while localized decreasing trends occur in the southern East Dian Plateau Basin and the northern Beipan River Plateau Canyon.Sunshine duration(SSD)is the dominant driving factor of ET0,maximum temperature(TMAX)contributes more significantly in high-altitude areas,minimum tempera-ture(TMIN)exhibits a compensatory effect,and wind speed(WIN)has the smallest contribution due to topographic constraints.Land use and topography have notable influences on ET0:shrubland presents the highest ET0 and bare land the lowest;while slope,elevation,and aspect indirectly affect ET0 by regula-ting local thermal-moisture conditions and wind speed.This study elucidates the main spatiotemporal characteristics and driving mechanisms of ET0 in the southwest karst region,providing a scientific basis for regional water resources management.