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  • Jul. 17, 2025

Arid Land Geography ›› 2025, Vol. 48 ›› Issue (5): 753-764.doi: 10.12118/j.issn.1000-6060.2024.395

• Climatology and Environment • Previous Articles     Next Articles

Spatiotemporal variation of actual evapotranspiration and its influencing factors in the northeast Qinghai-Xizang Plateau

LU Han1,2(), ZENG Yongnian1(), WANG Pancheng1   

  1. 1. School of Geosciences and Info-physics, Central South University, Changsha 410083, Hunan, China
    2. Guangzhou Urban Planning and Design Survey Research Institute Co., Ltd., Guangzhou 510060, Guangdong, China
  • Received:2024-06-25 Revised:2024-08-06 Online:2025-05-25 Published:2025-05-13
  • Contact: ZENG Yongnian E-mail:h_lu0123@163.com;ynzeng@csu.edu.cn

Abstract:

The spatiotemporal characteristics and influencing factors of actual evapotranspiration (ET) in the northeastern Qinghai-Xizang Plateau are crucial for the effective management of regional water resources and the ecological environment. Using Qinghai Province, located in this region, as the study area, this study analyzed actual ET data (MOD16 ET) from 2001 to 2020 to explore the spatiotemporal patterns, variation trends, and influencing factors over the past 20 years. The results indicate the following: (1) The average annual actual evapotranspiration in Qinghai Province from 2001 to 2020 was 260 mm·a-1, showing a fluctuating increasing trend. The fluctuation period also showed an increasing trend, with an average interannual change rate of 2%. Areas where actual ET increased accounts for 69.69% of the total area, and areas where it decreased accounted for 16.51%. Among them, the Qilian Mountains area and the eastern part of the river source ecological zone exhibited an increasing trend in actual ET. The seasonal variation of actual ET in Qinghai Province was significant, with the maximum in summer, the minimum in winter, and similar values in spring and autumn. (2) The average actual ET in Qinghai Province from 2001 to 2020 showed a spatial distribution characteristic of being low in the northwest and high in the southeast. There were large differences in actual ET among various ecological zones in Qinghai Province, with the Three River Source area and the Qilian Mountains area exhibiting the largest actual ET distribution, and the Qaidam Basin ecological zone had the smallest actual ET. The actual ET of the main vegetation cover types was ranked as follows: shrubland>forest land>grassland>arable land. (3) The fluctuating changes in actual ET in Qinghai Province from 2001 to 2020 were basically consistent with temperature variations. The increase in actual ET largely corresponded to the increasing trend of precipitation fluctuations, but the peak lagged behind changes in precipitation. (4) Actual ET was positively correlated with annual average temperature, annual total precipitation, sunshine duration, and average wind speed in 73%, 56%, 43%, and 44% of the total study area, respectively. Temperature and precipitation were the primary controlling factors of actual ET, whereas sunshine duration and wind speed also exerted notable influences. There were significant regional differences in the factors affecting the changes in actual evapotranspiration.

Key words: evapotranspiration, spatiotemporal variation, influencing factors, northeast Qinghai-Xizang Plateau, Qinghai Province