A doubled increasing trend of evapotranspiration on the Tibetan Plateau.

Estimation of evapotranspiration (ET) change on the Tibetan Plateau (TP) is essential to address the water requirement of billions of people surrounding the TP. Existing studies have shown that ET estimations on the TP have a very large uncertainty. In this article, we discuss how to more accurately quantify ET amount and explain its change on the TP. ET change on the TP can be quantified and explained based on an ensemble mean product from climate model simulations, reanalysis, as well as ground-based and satellite observations. ET on the TP experienced a significant increasing trend of around 8.4 ± 2.2 mm (10 a) (mean ± one standard deviation) during 1982-2018, approximately twice the rate of the global land ET (4.3 ± 2.1 mm (10 a)). Numerical attribution analysis revealed that a 53.8% TP area with the increased ET was caused by increased temperature and 23.1% part was due to soil moisture rising, because of the warming, melting cryosphere, and increased precipitation. The projected future increase in ET is expected to cause a continued acceleration of the water cycle until 2100.