Extremos Mínimos de Temperatura em tres Áreas no Sudeste da América do Sul em Simulações Climáticas do Clima Presente e no Cenário A2 do Clima Futuro

CAVALCANTI IRACEMA F.A; MÜLLER GABRIELA V.; ANDRADE KELEN; FERNANDEZ LONG MARIA ELENA; BIDEGAIN MARIO; BERRI GUILLERMO J.

Buenos Aires

Congreso; X Congreso Argentino de Meteorología y XIII Congreso Latinoamericano e Ibérico de Meteorología; 2009

Results of two Global Circulation Models (atmospheric and coupled)  were analyzed to identify  cases of cold air intrusion over southeastern South America, in three areas which are affected by frosts in Argentina, Uruguay and Brazil.  The analyzed control period  was 1961 to 1990, from may to september, and the IPCC A2 scenario, which reflects the extreme global warming, was used from 2081 to 2100, to the future climate. The general objective was the identification of cold air intrusion over southeastern South America in simulations of present climate and to investigate changes in the frequency of occurrence and atmospheric characteristics in a future climate scenario. The number of cold air intrusion is overestimated by CPTEC /COLA AGCM and coupled GFDL, which presents the largest differences. This systematic error must be considered in analyses of the future climate results. The frontal systems characteristics were well simulated by the models but the number of systems was overestimated. The composites of cases for the future climate indicated intensification of the temperature gradient,  intensification of frontal systems and the cold air extending to lower latitudes compared to the present climate. The more intense anomalies are related to the climatological mean, which is higher in the future than in the present. Therefore, even with less cold air intrusion over the southeastern Brazil, and a lower number of frost cases, the higher temperature reduction and the occurrence of more intense systems, would impact the agriculture.