Dipolar response of precipitation to lake expansion on the Tibetan Plateau

Abstract

Over the past half-century, lakes on the Tibetan Plateau (TP) have undergone significant expansion due to climate change. This expansion has previously unknown feedback on regional precipitation patterns. Here, using regional climate modeling experiments, we demonstrate that lake expansion induces a dipolar precipitation response across the TP, decreasing in the south and increasing in the north. Over 60 % of the southern region shows a decrease in annual precipitation, with an average reduction of −6.0 %. A meso-α-scale anticyclonic circulation anomaly, driven by lake-induced cooling, reduces vertical moisture advection and causes the decrease in precipitation, which accounts for 85 % of the changes. In contrast, more than 65 % of the northern region experiences an increase in precipitation, with an average rise of 7.2 %. Increased evaporation from expanded lakes drives the increased precipitation, accounting for 81 % of the changes. These findings highlight the importance of considering lake expansion feedback when evaluating water security on the TP in a warming world.