Impacts of Thermal Heating over the Tibetan Plateau on Atmospheric River Activity

We investigates the remote influence of diabatic heating over the Tibetan Plateau (TP) on atmospheric river (AR) activity in the North Pacific. We first identify a heating-sensitive region over the southern TP, where enhanced diabatic heating is significantly and positively correlated with AR frequency. This relationship is primarily associated with latent heat release sustained by abundant moisture supply. Further analyses indicate that the dynamical effects of eastward-propagating Rossby waves, originating over the Atlantic and modulated by the TP, promote upward moisture transport.Using the Water Accounting Model–2Layers, we show that the anomalous heating over the southern TP is mainly driven by increased moisture transport from the Indian Ocean, Arabian Sea, and Bay of Bengal, which is further intensified by the westward extension of the western North Pacific subtropical high (WNPSH). Additional moisture contributions are also detected from Eurasia. Moreover, Rossby wave activity emanating from the TP propagates eastward toward Japan, strengthening the westerlies and generating upper-level divergence that induces a coupled cyclonic–anticyclonic circulation over the North Pacific. This circulation enhances moisture convergence, thereby increasing AR activity in the region.In addition, a positive feedback is identified between southern TP heating and an eastward-propagating upper-level anticyclone, which further reinforces the westward extension of the WNPSH. These results highlight the TP’s far-reaching climatic influence and underscore its critical role in regulating atmospheric river activity over the North Pacific.