Tibetan Plateau warming and precipitation changes in East Asia

TLDR

Surface temperatures on the Tibetan Plateau have risen about 1.8 °C over the past 50 years, and the resulting precipitation pattern mirrors the dominant East Asian precipitation variability. Model experiments show that TP warming induces atmospheric heating that, through two Rossby wave trains and isentropic uplift, deforms the western Pacific Subtropical High and increases moisture convergence, thereby boosting East Asian subtropical frontal rainfall. The calculations link past TP warming to increased East Asian summer rainfall and project that future TP temperature rises will further intensify summer frontal precipitation in the region.

Abstract

Observational evidence presented here indicates that the surface temperatures on the Tibetan Plateau (TP) have increased by about 1.8°C over the past 50 years. The precipitation pattern that is projected as a result of this warming resembles the leading pattern of precipitation variations in East Asia (EA). Numerical experiments with atmospheric general circulation models show that atmospheric heating induced by the rising TP temperatures can enhance East Asian subtropical frontal rainfall. The mechanism of the linkage is found to be through two distinct Rossby wave trains and the isentropic uplift to the east of the TP, which deform the western Pacific Subtropical High and enhance moisture convergence toward the EA subtropical front. The model calculations suggest that the past changes in TP temperatures and EA summer rainfall may be linked, and that projected future increases in TP temperatures may lead to further enhanced summer frontal rainfall in EA region.