Distinct different climate evolution across inner Asia induced by the mountain building of the Tibetan Plateau and Central Asian Orogenic Belt

Abstract

<p>Incremental geological evidences reveal important climate reorganization in inner Asia and also the Asian mountain building since the late Oligocene-early Miocene. For the climate reorganization, the arid Asian inland has experienced several severe aridification periods and the Chinese Loess Plateau (CLP) shows abundant dust deposition from Red Clay in Neogene to loess-paleosol deposits in Quaternary. Meanwhile, more geological records indicate asynchronous growth of the Tibetan Plateau (TP) and the Central Asian Orogenic Belt (CAOB). Therefore, the question raises on how the stepwise growth of the TP and CAOB would influence the inner Asian climate reorganization. In order to answer the question, a set of numerical experiments is conducted by utilizing general circulation model CAM4. In the experiments, the main TP, Pamir Plateau (Pr), Tian Shan Mountains (TS) and Mongolian Plateau (MP) are successively included. Our modeling work shows that precipitation changes over arid inland and monsoon dominated CLP are different. With the inclusion of the main TP, Pr and TS, the precipitation and moisture reveal persistent reduction over the arid inland. On the contrary, the precipitation and moisture are significantly intensified over the CLP. The most intense decrease over the Tarim Basin (TB) is resulted by the inclusion of the main TP in warm season. Meanwhile, the increases over the CLP induced by the main TP and Pr-TS are comparable and both dominated in summer. After the final inclusion of the MP, the precipitation then reveal consistent reduction both over the arid inland and the CLP. The reduction is significant and dominated in summer. In addition, the precipitation in the TB portrays a spring-winter dominant pattern when the Pr and TS are removed. With the inclusion of the Pr-TS, the precipitation seasonality is transformed to peak in summer. Therefore, our results indicate the distinct differentiation of Asian climate regimes affected by the main TP, Pr, TS and MP. The results might provide new support for the evolution of Asian inland deserts  since the late Oligocene and the development of deposits over the CLP from Neogene Red Clay to Quaternary loess-paleosol deposits.</p>