A doubled increasing trend of evapotranspiration on the Tibetan Plateau

Estimation of evapotranspiration (ETa) 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 ETa estimations on the TP have a very large uncertainty. In this article, we discuss how to more accurately quantify ETa amount and explain its change on the TP. ETa 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. ETa on the TP experienced a significant increasing trend of around 8.4 ± 2.2 mm 10a-1 (mean ± one standard deviation) during 1982–2018, approximately twice the rate of the global land ETa (4.3 ± 2.1 mm 10a-1). Numerical attribution analysis revealed that a 53.8% TP area with the increased ETa 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 role of the increased temperature in ETa causes a continued acceleration of the water cycle in next 100 years.