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Modeling Southern Hemisphere Mid-latitude Precipitation Trends
Purich, A., Cowan, T., Min, S.-K. and Cai, W. 2013. Autumn precipitation trends over Southern hemisphere midlatitudes as simulated by CMIP5 models. Journal of Climate 26: 8341-8356.

The authors write that "in recent decades, Southern Hemisphere mid-latitude regions such as southern Africa, southeastern Australia, and southern Chile have experienced a reduction in austral autumn precipitation, the cause of which is poorly understood."

What was done
To see if they might better understand this shift in climate, Purich et al. analyzed "the ability of global climate models that form part of the Coupled Model Intercomparison Project phase 5 [CMIP5] to simulate these trends."

What was learned
The four researchers report that the CMIP5 models "underestimate both [1] the historical autumn poleward expansion of the subtropical dry zone and [2] the positive southern annular mode (SAM) trend." And they add that (3) a "multi-model ensemble was also unable to capture the spatial pattern of observed precipitation trends across semiarid mid-latitude regions."

What it means
In terms of Purich et al.'s stated purpose for conducting the analyses they performed, the CMIP5 models were clearly not up to the task required of them.

Reviewed 22 January 2014