Impacts Of Land-sea Distribution Over Southern Asia And The Southern Hemisphere On The Formation Of Asian Summer And Winter Monsoon

Using CCM3/NCAR model, a series of land-sea distribution scenarios are designed to investigate the impacts of the existence of the eastern continents (i.e. Indochina Peninsula, Marintime continents and Australia) and the western counterpart (i.e. Africa and Indian subcontinent) with 90° E as the divide, as well as the subplanetary land-sea distribution over southern Asia on the formation of the Indian monsoon system (IMS) and east Asian monsoon system (EAMS), the major conclusions being summarized as follows:(1) The presence of the land-sea thermal distribution comprised by the continents west of 90廕 and adjacent marginal seas is chiefly responsible for the formation of IMS but with few impacts on EAMS;(2) The thermal land-sea distribution resulted from the continents east of 90廕 and neighboring seas acts as an important role in the formation of EAMS, and also has effect on IMS somewhat;(3) The formation of the Bay of Bengal (BOB) intense rainfall and the southwesterly in summer and the northeasterly in winter are attributed to the coexistence of India and Indochina Peninsula, and moreover whose impacts are comparative, sc, the formation of BOB monsoon is affected by EAMS and IMS jointly;(4) Indochina Peninsula not only has key effects on the formation of EAMS, but influences IMS to some extent;(5) For the formation of IMS, the impact of Africa is greater than that of Indian subcontinent;(6) The presence of Indochina Peninsula and Marintime continents are crucial firstly to maintain the SCS summer monsoon seasonal variations, and the influence of Australia is secondly.(7) The circulation caused by the African continent over the southern hemisphere and the counterpart by Australian continent could interact with each other.(8) The presence of Africa, Indian subcontinent and Indochina Peninsula also have great impacts on the formation of the upper air subtropical jets, especially the two latter are very important for the maintenance of the subtropical jets to south of Tibetan Plateau, with greater effects of Indochina Peninsula comparatively.