How Mechanical and Thermal Forcing of the Tibetan Plateau Shapes the Northern Hemisphere Subtropical High

Abstract The subtropical high drives extreme weather and climate in mid‐low latitudes. While the summertime western Pacific subtropical high has been extensively studied, the hemisphere‐wide influence of the Tibetan Plateau (TP) on subtropical high remains less clear. Multi‐model simulations show that TP uplift intensifies and extends the Northern Hemisphere subtropical high northward in summer, while driving an overall intensification and expansion of the western Pacific subtropical high in winter. The mechanical effect of the TP dominates winter variability, whereas summer thermal forcing—peaking with diabatic heating—exerts a primary influence across the hemisphere. These impacts are mediated by atmospheric circulation. The reanalysis data further confirm the important role of TP thermal forcing in the observed variability of the subtropical high. Therefore, TP forcing is essential for understanding and predicting variability of the subtropical high throughout the Northern Hemisphere, beyond the western Pacific sector alone.