The role of climate change and vegetation greening on the variation of terrestrial evapotranspiration in northwest China's Qilian Mountains

Linshan Yang; Qi Feng; Jan F Adamowski; Mohammad Reza Alizadeh; Zhenliang Yin; Xiaohu Wen; Meng Zhu

doi:10.1016/j.scitotenv.2020.143532

The role of climate change and vegetation greening on the variation of terrestrial evapotranspiration in northwest China's Qilian Mountains

Sci Total Environ. 2021 Mar 10:759:143532. doi: 10.1016/j.scitotenv.2020.143532. Epub 2020 Nov 16.

Authors

Linshan Yang¹, Qi Feng², Jan F Adamowski³, Mohammad Reza Alizadeh³, Zhenliang Yin¹, Xiaohu Wen¹, Meng Zhu¹

Affiliations

¹ Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China; Qilian Mountains Eco-environment Research Center in Gansu Province, Lanzhou, Gansu 730000, China.
² Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China; Qilian Mountains Eco-environment Research Center in Gansu Province, Lanzhou, Gansu 730000, China. Electronic address: qifeng@lzb.ac.cn.
³ Department of Bioresource Engineering, Faculty of Agricultural and Environmental Sciences, McGill University, Québec H9X 3V9, CANADA.

PMID: 33250260
DOI: 10.1016/j.scitotenv.2020.143532

Abstract

Terrestrial evapotranspiration (ET_a) reflects the complex interactions of climate, vegetation, soil and terrain and is a critical component in water and energy cycles. However, the manner in which climate change and vegetation greening influence ET_a remains poorly understood, especially in alpine regions. Drawing on the Global Land Evaporation Amsterdam Model (GLEAM) ET_a data, the interannual variability of ET_a and its ties to precipitation (P), potential evaporation (ET_p) and vegetation (NDVI) were analysed. The Budyko framework was implemented over the period of 1982 to 2015 to quantify the response of ET_a to climate change's direct (P and ET_p) and indirect (NDVI) impacts. The ET_a, P, ET_p and NDVI all showed significant increasing trends from 1981 to 2015 with rates of 1.52 mm yr^-1, 3.18 mm yr^-1, 0.89 mm yr^-1 and 4.0 × 10^-4 yr^-1, respectively. At the regional level, the positive contribution of increases in P and NDVI offset the negative contribution of ET_p to the change in ET_a (∆ET_a). The positive ∆ET_a between 1982 and 2001 was strongly linked with the concomitant increase in NDVI. Increases in vegetation contributing to a positive ∆ET_a differed among landscape types: for shrub, meadow and steppe they occurred during both periods, for alpine vegetation between 1982 and 2001, and for desert between 2002 and 2015. Climate change directly contributed to a rise in ET_a, with P as the dominant factor affecting forested lands during both periods, and alpine vegetation between 2002 and 2015. Moreover, ET_p was a dominant factor for the desert between 1982 and 2001, where the variation of P was not significant. The contributions of factors having an impact on ∆ET_a are modulated by both the sensitivity of impact factors acting on ET_a as well as the magnitudes of factor changes. The greening of vegetation can influence ET_a by increasing vegetation transpiration and rainfall interception in forest, brush and meadow landscapes. These findings can help in developing a better understanding of the interaction of ecosystems and hydrology in alpine regions.

Keywords: Budyko hypothesis; Climate change; Qilian Mountains; Terrestrial evapotranspiration; Vegetation greening.

MeSH terms

China
Climate Change*
Ecosystem*
Water

Substances

Water