The impact of regional uplift of the Tibetan Plateau on the Asian monsoon climate

The climatic effect of Tibetan Plateau (TP) uplift is a hot topic in paleoclimate research. In this paper, the results of a set of numerical simulations are reported to analyze the impact of regional TP uplift on the Asian monsoon climate. The focus is on the impact of the regional uplift in the west and east parts on South Asian summer monsoon, as well as the impact of regional uplift on East Asian winter monsoon. The results show that the uplifts of the Himalaya and the central-southern TP have little effect on summer precipitation increasing over South Asia. Whereas, the further uplifts of the TP in the west and east parts, including the uplifts of both the eastern and western TP, have important effects on the strengthening of the South Asian summer monsoon. The uplift of the eastern TP leads to low-level cyclonic circulation anomalies appearing in the Bay of Bengal, accompanied by anomalous upward movement, and in turn precipitation markedly increases in the Bay of Bengal. Whereas, the uplift of the western TP produces low-level cyclonic circulation anomalies around the uplifted region and intensifies the moisture transport from the tropical ocean, and thus precipitation further increases in South Asia, especially in the northern Arabian Sea. The strengthened summer monsoon in South Asia is coupled with the intensification in diabatic heating and moisture convergence. For the East Asian winter monsoon, the intensification of winter monsoon winds is related more to the regional uplifts than the uplift of the whole TP. The uplifts of the central-southern TP, the northern TP and other northern topography have greater effects on the strengthening of the winter monsoon winds.