基于Budyko模型的渭河流域蒸散发时空变化归因分析

Analysis of Spatiotemporal Variation and Attribution of Evapotranspiration in Weihe River Basin Based on Budyko Model

[目的]定量评估渭河流域蒸散发变化趋势,分析其对环境变化的响应,有利于该区域水资源变化的研究。[方法]基于Budyko框架,结合归一化植被指数、土地利用类型、GLEAM蒸散发遥感数据、气象水文和社会经济等数据分析各驱动要素的趋势,构建了时变Budyko参数n的经验模型,采用弹性系数法定量评估各要素变化对蒸散发的影响。[结果](1) 1990—2020年渭河流域实际蒸散发呈现显著增长的趋势,整体增速为1.98 mm/a,空间上呈东南向西北逐渐减少的趋势。(2)渭河流域下垫面参数n呈现增长的趋势,参数n与该地区的NDVI、人口、耕地面积、草地和GDP相关性较高。在对蒸散发模拟时,时变参数n模拟蒸散发的精度整体优于恒定参数n。(3)渭河流域蒸散发对降水量最敏感,对下垫面参数n不敏感,下垫面参数n对NDVI最敏感。(4)影响蒸散发变化程度大小依次为降水、下垫面参数、潜在蒸散发。[结论]研究时段内渭河流域蒸散发呈现显著增长趋势,气候变化对该地区蒸散发的变化起着主导作用,但人类活动对蒸散发的影响越来越明显。

[Objective] The aim of this study is to quantitatively assess the evapotranspiration trends and analyze its response to environmental changes in the Weihe River Basin,so as to be conducive to the study of water resources change in this region.[Methods] Based on the Budyko framework and combined with NDVI,land use type,GLEAM evapotranspiration remote sensing data,meteorological and hydrological data and social and economic data,the trend of each driving factor was analyzed,an empirical model of time-varying Budyko parameter n was constructed,and the elastic coefficient method was adopted to quantitatively evaluate the influence of each factor change on evapotranspiration.[Results](1) From 1990 to 2020,the actual evtranspiration in the Weihe River Basin showed a significant growth trend,with the overall growth rate of 1.98 mm/a,and the spatial trend was gradually decreasing from southeast to northwest.(2) The hydrothermal parameter n of the underlying surface of the Weihe River Basin showed an increasing trend,and parameter n had a high correlation with the NDVI,population,cultivated land area,grassland and GDP of the region.In the simulation of evapotranspiration,the results of the empirical model with time-varying parameter n are better than those with constant parameter n.(3) Evapotranspiration in Weihe River Basin was the most sensitive to precipitation,but not to underlying surface parameter n,which was most sensitive to NDVI.(4) Precipitation contributed the most to evapotranspiration,followed by underlying surface factors,and potential evapotranspiration contributed the least.[Conclusion] Evapotranspiration in the Weihe River Basin showed a significant increase trend during the study period,and climate change played a leading role in the change of evapotranspiration in this region,but the influence of human activities on evapotranspiration became more and more obvious.