Climate modelling study on mountain uplift and Asian monsoon evolution
A. Kitoh, T. Motoi, O. Arakawa, 2010. "Climate modelling study on mountain uplift and Asian monsoon evolution", Monsoon Evolution and Tectonic–Climate Linkage in Asia, P. D. Clift, R. Tada, H. Zheng
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Impacts of mountain uplift on the Asian monsoon and adjacent seas are investigated by climate model sensitivity studies. Two sets of general circulation model (GCM) experiments are performed. Using an atmosphere-ocean coupled GCM, a progressive mountain uplift experiment is performed. During boreal summer, monsoon precipitation is confined in the deep tropics around 10°N in the no-mountain case, but as mountains become higher, heavy rain areas move inland from the East Asian coast with stronger upward winds and increased rainfall over the southeastern Tibetan Plateau region. An increase of freshwater discharge from the Asian rivers results in a significant decrease of sea surface salinities over the Bay of Bengal, the South China, East China and Yellow Seas. A high-resolution atmospheric GCM experiment, which shows improvement in reproducing the present-day model climatology, gives more precise information on precipitation and the circulation changes caused by mountain uplift.
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The Earth’s climate varies through geological time as a result of external, orbital processes, as well as the positions of continents, growth of mountains and the opening and closure of oceanic gateways. Climate modelling suggests that the intensity of the Asian monsoon should correlate, at least in part, with the uplift history of the Tibetan Plateau and the Himalaya, as well as the evolution of gateways and the retreat of shallow seas in Central Asia. Long-term reconstructions of both mountain building and monsoon activity are key to testing the proposed links. This collection of papers presents a series of new studies documenting the variations of the Asian monsoon on orbital and tectonic timescales, together with the impact this has had on environmental conditions. The issue of which proxies are best suited to measuring monsoons is addressed, as is the effect that the monsoon has had on erosion and the formation of the stratigraphic record both on and offshore.