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.
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.
Sci Total Environ. 2021 Mar 10;759:143532. doi: 10.1016/j.scitotenv.2020.143532. Epub 2020 Nov 16.
Terrestrial evapotranspiration (ET) 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 remains poorly understood, especially in alpine regions. Drawing on the Global Land Evaporation Amsterdam Model (GLEAM) ET data, the interannual variability of ET and its ties to precipitation (P), potential evaporation (ET) and vegetation (NDVI) were analysed. The Budyko framework was implemented over the period of 1982 to 2015 to quantify the response of ET to climate change's direct (P and ET) and indirect (NDVI) impacts. The ET, P, ET and NDVI all showed significant increasing trends from 1981 to 2015 with rates of 1.52 mm yr, 3.18 mm yr, 0.89 mm yr and 4.0 × 10 yr, respectively. At the regional level, the positive contribution of increases in P and NDVI offset the negative contribution of ET to the change in ET (∆ET). The positive ∆ET between 1982 and 2001 was strongly linked with the concomitant increase in NDVI. Increases in vegetation contributing to a positive ∆ET 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 with P as the dominant factor affecting forested lands during both periods, and alpine vegetation between 2002 and 2015. Moreover, ET 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 are modulated by both the sensitivity of impact factors acting on ET as well as the magnitudes of factor changes. The greening of vegetation can influence ET 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.
陆地蒸散量（ET）反映了气候、植被、土壤和地形的复杂相互作用，是水和能量循环的关键组成部分。然而，气候变化和植被绿化如何影响 ET 的方式仍知之甚少，尤其是在高山地区。本研究利用全球陆地蒸散量阿姆斯特丹模型（GLEAM）的 ET 数据，分析了 1982 年至 2015 年期间 ET 的年际变化及其与降水（P）、潜在蒸散（ET）和植被（NDVI）的关系。利用 Budyko 框架量化了 ET 对气候变化直接（P 和 ET）和间接（NDVI）影响的响应。1981 年至 2015 年期间，ET、P、ET 和 NDVI 均呈显著增加趋势，增长率分别为 1.52mm yr、3.18mm yr、0.89mm yr 和 4.0×10 yr。在区域水平上，P 和 NDVI 增加的正贡献抵消了 ET 对 ET 变化（∆ET）的负贡献。1982 年至 2001 年期间，∆ET 与 NDVI 的同时增加密切相关。促进正 ∆ET 的植被增加因景观类型而异：对于灌木、草地和草原，它们在两个时期都发生；对于高山植被，它们发生在 1982 年至 2001 年期间；对于沙漠，它们发生在 2002 年至 2015 年期间。气候变化直接导致 ET 增加，其中 P 是两个时期影响林地的主导因素，2002 年至 2015 年期间影响高山植被。此外，1982 年至 2001 年期间，ET 是沙漠的主导因素，而 P 的变化并不显著。影响 ∆ET 的因素的贡献受到影响 ET 的作用因素的敏感性以及因素变化幅度的调节。植被绿化可以通过增加森林、灌丛和草地景观中的植被蒸腾和降雨截留来影响 ET。这些发现有助于更好地理解高山地区生态系统和水文学的相互作用。
