Impacts of glacier changes on precipitation in the Tibetan Plateau

Abstract. The Tibetan Plateau (TP) harbors the largest expanse of glaciers at middle and high latitudes globally. Against the backdrop of ongoing global warming, TP glaciers have experienced widespread retreat and significant mass balance alterations in recent decades, raising questions about their impact on regional climate. In this study, we address this knowledge gap by investigating the magnitude and spatial extent of precipitation responses to glacier changes across the TP using four distinct Weather Research and Forecasting (WRF) simulations reflecting different glacier and climate conditions. Our findings reveal that, on average, mean precipitation (except for winter) tends to diminish by approximately 0.6 % to 2.0 % during a cold year and increases by about 0.2 % to 2.5 % during a warm year over most grid cells influenced by glacier alterations. Additionally, glacier changes lead to a reduction (or augmentation) of summer mean precipitation by an average of 0.6 % to 5.2 % (1.2 % to 10.7 %) over different regions of the TP during the cold (warm) years, accompanied by a notable increase of 0.8 % to 19.7 % in summer extreme precipitation, irrespective of climate conditions. In general, glacier changes exert a more pronounced impact on summer extreme precipitation events than mean precipitation, with an average increase of 1.7 % and 4.6 % over the whole TP during the cold and warm years, respectively. Moreover, glacier changes in warmer climate conditions tend to increase summer precipitation amounts in high-altitude areas when the water supply is adequate.