Acta Geographica Sinica ›› 2023, Vol. 78 ›› Issue (11): 2750-2762.doi: 10.11821/dlxb202311007

• Surface Process • Previous Articles     Next Articles

Attribution analysis of changes in terrestrial evapotranspiration in China during 1982-2019

BAI Peng1(), CAI Changxin1,2   

  1. 1. Key Laboratory of Water Cycle and Related Land Surface Process, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2023-06-29 Revised:2023-11-05 Online:2023-11-25 Published:2023-11-29
  • Supported by:
    The Third Xinjiang Scientific Expedition Program(2021xjkk0806);National Natural Science Foundation of China(42271033);National Natural Science Foundation of China(51979263)

Abstract:

Evapotranspiration (ET) is one of the key components of the terrestrial water cycle, and its long-term changes directly affect the spatiotemporal pattern of regional water availability. In recent decades, China has experienced significant changes in climate and land surface characteristics. However, how these changes affected the spatiotemporal pattern of terrestrial ET was still poorly understood. In this study, we quantified the contributions of five factors related to climate and vegetation (precipitation, wind speed, vapor pressure deficit, net radiation, and leaf area index) to ET trends across China using the Penman-Monteith-Leuning model and a forcing variable detrending experiment. The results showed that nationwide annual ET increased significantly (p < 0.05) from 1982 to 2019, with a trend of 1.25 mm a-1. Vapor pressure deficit, leaf area index and precipitation dominated the national ET changes, and their contributions to ET trends are 42% (0.54 mm a-1), 29% (0.36 mm a-1), and 27% (0.31 mm a-1), respectively. Spatially, the dominant factors of ET changes show clear regional differences. Changes in ET are dominated by precipitation in the arid and semi-arid regions of northwestern China, and by vapor pressure deficit in humid regions such as the Yangtze River basin and the northern part of northeastern China. Leaf area index dominates ET changes in areas with a significant greening such as the Loess Plateau, North China Plain and parts of Northeast China. The findings are expected to provide guidance for national water resources management and planning under climate change.

Key words: evapotranspiration, water cycle, climate change, vegetation greening