chapter - Atmospheric and Oceanic Science

Correlations between CPTEC/COLA AGCM results and observation precipitation
anomalies are presented in figure 13.5. There are high correlation values over
northern and northeastern South America and some areas over the La Plata basin
region with values above 60% in summer, autumn and spring, increasing the confidence
on the model results during these seasons.
Differences between surface mean annual temperatures of the NCEP/NCAR
reanalyses (Kalnay et al. 1996) and those of four GCMs indicate that models tend
to overestimate the temperature in most of Buenos Aires province, Northeast of
Argentina, Uruguay and South of Brazil and underestimate it in a longitudinal strip
centred approximately at 62.5ºW. The model that best represents the mean annual
temperature of this region is HadCM3 that overestimates temperature between 0º
and 1.5ºC.
13.4. Regional scenarios for the La Plata basin
13.4.1. Hadley Centre GCM
Regional climatic scenarios
Fig. 13.4. Precipitation anomaly over South Brazil and Uruguay from nine integrations (CPTEC/COLA
AGCM) and CMAP, in JJAS.
[Source: Marengo et al 2003]
Using the Hadley Centre GCM outputs for the emission scenarios A2 and B2,
the differences between projected precipitation for the decades 2020, 2050 and
2080 and the reference period (1961-1990), are in figures 13.6 and 13.7. Results
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