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The Indo-Australian Monsoon in CMIP3 and CMIP5 Simulations
Jourdain, N.C., Gupta, A.S., Taschetto, A.S., Ummenhofer, C.C., Moise, A.F. and Ashok, K. 2013. The Indo-Australian monsoon and its relationship to ENSO and IOD in reanalysis data and the CMIP3/CMIP5 simulations. Climate Dynamics 41: 3073-3102.

The authors state that the Indo-Australian monsoon consists of two parts: the Indian and South-East Asian summer monsoon that occurs from June to September (JJAS), and the Australian and Maritime Continent monsoon that occurs in austral summer (December to March, DJFM)," while noting that the appellation Maritime Continent includes the region of Southeast Asia that consists of Indonesia, the Philippines, Papua New Guinea and several other countries that are situated between the Indian and Pacific Oceans within a warm ocean region known as the Tropical Warm Pool.

What was done
Jourdain et al. studied the Indo-Australian monsoon and its teleconnections with the ENSO (El Niņo Southern Oscillation) and IOD (Indian Ocean Dipole) phenomena, as expressed in CMIP (Coupled Model Intercomparison Project) simulations. This they did by performing a combined analysis of simulations derived from 24 CMIP3 models and 35 newer - and supposedly improved - CMIP5 models, comparing the model projections with results from seven atmospheric reanalyses that they say "are often used as a proxy for dynamical observations (e.g. wind, pressure) to evaluate the CMIP model dynamics, or to analyze mechanisms."

What was learned
When all was said and done, the six scientists had determined, in their words, that "the best CMIP5 models have stronger skills than the best CMIP3 models." However, they go on to say that these so-called best models "are still unable to resolve the [climatic] complexity of the Maritime Continent," especially as it applies to monsoonal activity.

What it means
In light of this latter demonstrable fact, Jourdain et al. say that this situation "leads to the absence of model consensus concerning the future monsoon rainfall in this region." And this means that we are still not at a point where we can adequately characterize the nature of the studied region's climate of the future with any significant degree of confidence.

Reviewed 12 March 2014