Effect of sub‐cloud evaporation on precipitation in the Tianshan Mountains (Central Asia) under the influence of global warming

Abstract

AbstractIt is crucial for accurately describing the precipitation patterns and their underlying mechanisms to optimise the hydro‐climatic model parameters and improve the accuracy of precipitation forecasting. Based on 212 precipitation samples collected during August 2015 to July 2016 in the mid‐mountain region of the Manasi River Basin in the northern slope of the Tianshan Mountains, we estimated the effect of sub‐cloud evaporation on precipitation, analysed the factors that influence the sub‐cloud evaporation, and modelled the response of sub‐cloud evaporation to global warming. The mean remaining raindrop mass fraction after evaporation (f) in this region is 94.39%. The mean deviation between d‐excess (Δd) of ground precipitation and raindrops under cloud is −4.22‰. The intensity of sub‐cloud evaporation is the highest in summer. There is a significant positive correlation between f and Δd (0.72‰/%). The relative humidity and diameter of raindrops were observed to have a direct influence on the intensity of sub‐cloud evaporation. The temperature was observed to influence the intensity of sub‐cloud evaporation indirectly by influencing the relative humidity and diameter of raindrops. Global warming will increase the intensity of sub‐cloud evaporation in the Tianshan Mountains, especially for small precipitation events.