Differentiation of Asian summer precipitation induced by the mountain building of the Tibetan Plateau and Central Asian Orogenic Belt

Abstract

Geological records from the representative monsoon-aridity climate regimes, the Chinese Loess Plateau (CLP) and Tarim Basin (TB), demonstrate that the climate has experienced distinct reorganization since the late Oligocene/early Miocene. Meanwhile, incremental evidence indicates asynchronous growth of the Tibetan Plateau (TP) and Central Asian Orogenic Belt. Therefore, how the growth of these topographies affects the Asian climate regimes need further numerical examination. By successively including the main TP, Pamir Plateau (Pr), Tian Shan Mountains (TS) and Mongolian Plateau (MP) in our numerical experiments, the effects of the stepwise uplift are examined. For the arid interior, the main TP, Pr, TS and MP all cause significant reduction of precipitation and moisture, presenting a persistent aridification process. The most intense reduction is resulted by the main TP in warm season. The summer precipitation over the CLP experienced a persistent intensification with the uplift of the main TP, Pr and TS, indicating a persistent strengthening of the East Asian summer monsoon. After that, the summer precipitation over the CLP is suppressed with the MP uplift, which is consistent with the MP-induced decrease over the arid inland. The annual mean precipitation change over the CLP resembles the change in summer. Therefore, the topography-induced precipitation evolution over the TB and CLP exhibits different processes. Meanwhile, the precipitation over the TB initially portrays a spring-winter dominant pattern as the TP significantly suppressed the precipitation in summer. The summer precipitation is then intensified with the inclusion of the Pr-TS and the precipitation seasonality is transformed to peak in summer. The results indicate the differentiation of Asian climate regimes affected by the main TP, Pr-TS and MP. The results might provide new support for the evolution of mid-latitude deserts and Neogene Red Clay and Quaternary loess-paleosol deposits on the CLP since the late Oligocene.