Climate variability and change in South America from WCRP/CMIP3 Models
Carolina Vera, CIMA, Univ. of Buenos Aires, Argentina
An assessment of the ability of 20th-century simulations from the WCRP/CMIP3 models in reproducing the seasonal, intraseasonal and year-to-year climate variations in South America will be presented. In addition, climate change projections over South America and the associated uncertainty issues will be also discussed
Models are able to reproduce in some extent the basic features of the precipitation seasonal cycle over South America; although the precipitation amounts in the SACZ, monsoon core, and La Plata Basin regions are not well represented. The spatial patterns of precipitation variability on interannual and intraseasonal time scales are somewhat represented by some of the models, although they lack in describing correctly the remote influence of forcing like ENSO, AAO. There is a generalized consensus among models that seasonal precipitation changes projected for the second half of 21C are mainly an increase of precipitation over southeastern subtropical South America and reduction along the southern Andes. However, current climate model projections over South America still exhibit a considerably large range of uncertainties that need to be reduced. Moreover, the physical explanation of those climate changes is not clear yet. Changes in the storm tracks as well as in the mean conditions of the tropical regions might have a role in explaining them.
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