Land-sea thermal contrast, topography, moist processes, and Earth’s rotation determine monsoon rainfall patterns and vigor (Webster 1987). The obtained monsoon precipitation domains include all regional monsoons over South Asia, East Asia, western North Pacific (WNP), Australia, Africa and Americas (Wang and Ding 2008). In contrasting to the traditional definition of monsoon using surface winds (Ramage 1971), recent studies define monsoon domains in terms of the precipitation characteristics (Wang 1994). The response yields a unique monsoon climate regime characterized by an annual reversal of surface winds and contrasting rainy summer and dry winter. Physically, monsoon is a forced response of the coupled atmosphere-land-ocean climate system to the annual variation of insolation. (4) The spatial structures of the leading mode of interannual variation of AAM precipitation will not change appreciably but the ENSO-AAM relationship will be significantly enhanced. (3) The Asian monsoon domain over the land area will expand by about 10 %. Different from the CMIP3 analysis, the EA subtropical summer monsoon circulation will increase by 4.4 %/☌. (2) The low-level tropical AAM circulation will weaken significantly (by 2.3 %/☌) due to atmospheric stabilization that overrides the effect of increasing moisture convergence. ![]() The combined effects explain the differences between the Asian and Australian monsoon changes. On the other hand, the warm Northern Hemisphere-cool Southern Hemisphere induced hemispheric SLP difference favors the ASM but reduces the Australian summer monsoon rainfall. The “warm land-cool ocean” favors the entire AAM precipitation increase by generation of an east-west asymmetry in the sea level pressure field. ![]() (1) The total AAM precipitation (as well as the land and oceanic components) will increase significantly (by 4.5 %/☌) mainly due to the increases in Indian summer monsoon (5.0 %/☌) and East Asian summer monsoon (6.4 %/☌) rainfall the Australian summer monsoon rainfall will increase moderately by 2.6 %/☌. The future projections made by the selected multi-model mean suggest the following changes by the end of the 21st century. The CMIP5 models are more skillful than the CMIP3 models in terms of the AAM metrics. A metrics for evaluation of the model’s performance on AAM precipitation climatology and variability is used to select a subset of seven best models. We investigate the future changes of Asian-Australian monsoon (AAM) system projected by 20 climate models that participated in the phase five of the Coupled Model Intercomparison Project (CMIP5).
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