黄土高原农业区蒸散发时空演变与环境因子贡献研究

Spatiotemporal Evolution of Evapotranspiration and Contribution of Environmental Factors in Loess Plateau Agricultural Region

摘要:

黄土高原农业区作为我国重要的农业生产区域，其水资源紧张与生态环境脆弱的特点使得蒸散发（ET）的时空演变及其与环境因子的关系研究对水资源管理与生态恢复具有重要意义。本研究基于2005—2020年MODIS卫星数据，结合叶面积指数（LAI）、降水量（PRE）、气温（Ta）、土壤含水量（SM）、地表太阳辐射（SSR）等环境因子，系统分析了黄土高原农业区ET的时空演变特征及其驱动机制。主要研究结论：全年ET和夏季ET的空间分布呈现自西北至东南递增的趋势，且分别有91.46%和88.41%的区域呈现显著上升趋势（p<0.05）；ET变化的上升趋势具有较强持续性，且夏季ET变化主导全年ET变化，；LAI和SM在全年及夏季ET变化中主导作用显著，LAI在全年贡献55.92%，SM在夏季贡献23.28%，此外，全年SSR对ET的影响大于PRE和Ta，而夏季PRE对ET影响更大，表明主导因素在不同时间尺度上有所不同；植被恢复有助于生态修复，但可能加剧水资源短缺，未来策略需考虑水资源承载力，以确保生态与水资源的协调发展。本研究揭示了黄土高原农业区ET时空演变特征及其驱动机制，为区域水资源管理和生态恢复提供了科学依据。

Abstract:

The Loess Plateau agricultural area, a critical agricultural production zone in China, is characterized by severe water scarcity and ecological vulnerability. To support water resource management and ecological restoration, a systematic study was conducted on the spatiotemporal evolution of evapotranspiration (ET) and its driving mechanisms. Based on MODIS satellite data (2005—2020), key environmental factors were integrated, including leaf area index (LAI), precipitation (PRE), air temperature (Ta), soil moisture (SM), and surface solar radiation (SSR). The following results were obtained, the spatial distribution of annual and summer ET exhibited a northwest-to-southeast increasing gradient, with 91.46% and 88.41% of the area showing a significant upward trend (p<0.05), respectively. The increasing trend of ET was found to be persistent, and summer ET variations were identified as the primary driver of annual ET changes. LAI and SM were demonstrated to dominate annual and summer ET variations, contributing 55.92% (annual) and 23.28% (summer), respectively. Additionally, SSR exerted a stronger influence on ET than PRE and Ta at the annual scale, whereas PRE played a more significant role in summer, indicating time-scale-dependent dominant factors. Vegetation restoration was shown to promote ecological recovery but might intensify water shortages. Thus, future strategies must account for water resource carrying capacity to balance ecological and hydrological sustainability. The research result can provide scientific insights into ET dynamics in the Loess Plateau agricultural area, offering a basis for regionally tailored water and ecosystem management.