Climatic variability on the intrazonal scale in the Southern Hemisphere with emphasis on the influences on South America and Southeast Brazil: the behavior of the CPTEC/COLA model of global circulation of the atmosphere

• Grant number: 02/07424-6
• Support type: Regular Research Grants
• Duration: May 01, 2003 - June 30, 2005
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Meteorology
• Principal researcher: Iracema Fonseca de Albuquerque Cavalcanti
• Grantee: Iracema Fonseca de Albuquerque Cavalcanti
• Home Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brasil). São José dos Campos , SP, Brazil

Abstract

It has been observed, in results of forecasting and seasonal simulation, that the Southeast region of Brazil is the region with the lowest predictability in the country. This is a transition region between the tropical region of the north and the extratropical region to the south, affected by synoptic systems which can be the result of the model, have different behaviors, not necessarily the same as those observed. Also shown, in some observational studies, has been the influence of trains of low frequency waves and of oscillation from 30 to 60 days, on the Southeast region of Brazil. Considering that intraseasonal anomalies, such as blockades, oscillations of 30 to 60 days and patterns of low frequency teleconnection can affect the behavior of synoptic systems that act on the South American continent, it is important to know whether a model of general circulation is capable of reproducing the low frequency variability that can influence the high frequency. The proposal of this work is to analyze the atmospheric variability of the Southern hemisphere, on the intraseasonal scale, simulated by the MCGA Cptec/Cola, comparing with the variability observed on this scale and establishing the dominance of patterns for some bands of frequency, to elaborate indices associated with the patterns of teleconnections identified. It is hoped that the comparison of the indices obtained in the analyses with the data from the model and observational data and the verification of the influence of extreme indices in the atmospheric conditions above South America and the Southeast of Brazil may contribute to a better understanding of the action of the low frequency and of the behavior of the model in these regions, with a view to better seasonal forecasts. (AU)