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ENSO-Induced Rainfall Changes Derived from CMIP5 AOGCMs

Paper Reviewed
Steinhoff, D.F., Monaghan, A.J. and Clark, M.P. 2015. Projected impact of twenty-first century ENSO changes on rainfall over Central America and northwest South America from CMIP5 AOGCMs. Climate Dynamics 44: 1329-1349.

Writing as background for their study, Steinhoff et al. (2015) state that "due to the importance that the El Niño-Southern Oscillation (ENSO) has on rainfall over the tropical Americas, future changes in ENSO characteristics and teleconnections are important for regional hydroclimate." And, therefore, they explored projected changes to ENSO mean state and its primary characteristics -- along with resulting impacts on rainfall anomalies over Central America, Colombia and Ecuador during the 21st century -- for several different forcing scenarios, using "a suite of coupled atmosphere-ocean global climate models (AOGCMs) from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). And what did they thereby learn?

The three U.S. researchers found that (1-3) "current and projected future characteristics of ENSO (frequency, duration, amplitude) show a wide range of values across the various AOGCMs," that (4) "the magnitudes of ENSO-related rainfall anomalies are currently underestimated by most of the models," and that (5) "there is not agreement on the changes in ENSO-related rainfall anomalies in future simulations." And with no agreement among the models on this extremely basic point, there is essentially nothing new -- or necessarily true -- that they have to tell us about the subject.

Posted 29 June 2015