Evaluation of the WCRP-CMIP3 model simulations in the La Plata basin

In this article. an assessment of the climate simulations for the La Plata Basin (LPB) by the Phase 3 of the World Climate Research Programme - Coupled Model Intercomparison Project is made. The LPB covers a wide area over south-eastern South America. and is the fifth largest basin in the world in terns of geographical extent. It was found that the observed warm summer - cold winter pattern of temperature is well represented by the climate models but they have deficiencies in reproducing the monthly mean temperature values. The largest differences take place during, spring and summer. seasons in which the models exhibit temperatures higher than observations. Models are able to represent the annual cycle of precipitation in the north of the LPB but some deficiencies are observed in the centre and south. In addition. there is an overestimation of heavy (light) rain events at the northern (central and southern) portion of the basin. Results also show that the projected precipitation future change is positive in autumn and winter in the northern LPB as well as in most of the year in the centre and south of the basin. The precipitation distributions Show an increase (decrease) in the frequency of low rainfall (heavy rainfall) events in the north of LPB and opposite change in the centre and south. Nevertheless. considerable inter-model variability is found in the representation of the precipitation features at both present and future climate that make quite uncertain the quantification of those projected changes. Copyright (C) 2008 Royal Meteorological Society