关键词: 蒸散发, MODIS ET数据, 黄土高原, 土地利用, 耗水特征

Abstract: Accurate assessments of the spatiotemporal variations of actual evapotranspiration (ET) and the impact of land use changes on ET are crucial for the rational utilization and optimal allocation of regional water resources. With MOD16A2 data as the primary data source, we analyzed the spatiotemporal distribution and trends of actual ET of Loess Plateau from 2000 to 2022 by Theil-Sen trend analysis and Mann-Kendall test. Additionally, land use data were incorporated to examine the variations in ET across the primary land use types within the study area and to estimate the regional water consumption. The results showed that: (1) Actual average daily ET in the Loess Plateau exhibited annual fluctuations with an overall increasing trend, ranging from 0.52 to 0.97 mm, with an average daily increase rate of 0.015 mm·a^-1. Spatially, ET values showed an increasing trend from the northwest to the southeast of the region. (2) Among the four dominant land use types, the annual average evapotranspiration followed an order: forest land > cultivated land > grassland > unused land. (3) From 2000 to 2020, the cultivated land area in the Loess Plateau decreased by 13377.0 km², with a reduction rate of 6.2%. In contrast, forest land area increased significantly by 3748.6 km², primarily due to the “Grain for Green” policy, while constructed land increased by 11657.8 km². (4) The trend in water consumption was consistent with the changes in land use areas, showing an overall increasing trend from 2000 to 2020. These findings provide a robust scientific foundation for the sustainable utilization and allocation of water resources in the Loess Plateau, particularly under the context of the “Grain for Green” policy.

Key words: evapotranspiration, MODIS ET data, Loess Plateau, land use, water consumption characteristic