CMIP5 Model Simulations of the Earth's Western Pacific Monsoon
Brown, J.R., Colman, R.A., Moise, A.F. and Smith, I.N. 2013. The western Pacific monsoon in CMIP5 models: Model evaluation and projections. Journal of Geophysical Research: Atmospheres 118: 12,458-12,475.
In describing their findings the four Australian researchers report (1) they "identified a number of biases including westerly summer monsoon winds that do not extend far enough east in many models," (2) "the AMIP [Atmospheric Model Intercomparison Project] models do not simulate the seasonal cycle of rainfall substantially better than CMIP5 [by] failing to capture the correct seasonal cycle over the Palau domain," (3) "both CMIP5 and AMIP models appear to share problems in simulating the processes producing tropical rainfall, such as deep convection," (4) CMIP5 models tend to simulate the boundary between positive and negative anomalies too far west," which leads to (5) "incorrect sign anomalies over the Solomon Islands," and (6) the models "substantially underestimate negative rainfall anomalies over the Maritime Continent region (including New Guinea and Timor)."
In the final sentence of their paper, Brown et al. conclude "further investigation of the mechanisms determining the response of the monsoon in individual models is required to understand the reasons for model disagreement and to determine which aspects of projected monsoon change are most robust."
Smith, I., Moise, A.F. and Colman, R.A. 2012. Large-scale circulation features in the tropical western Pacific and their representation in climate models. Journal of Geophysical Research 117: 10.1029/2011JD016667.
Sperber, K.R., Annamalai, H., Kang, I.-S., Kitoh, A., Moise, A., Turner, A., Wang, B. and Zhou, T. 2013. The Asian summer monsoon: An intercomparison of CMIP5 vs. CMIP3 simulations of the late 20th century. Climate Dynamics 41: 2711-2744.