Storm-track na América do Sul e vizinhanças: climatologia, variabilidade e mudanças climáticas / Storm-tracks over South America and adjacent areas: climatology, variability and climate change

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

This study deals with an extratropical cyclone climatology for South America (SA), Antarctic Peninsula and adjacents oceans in the austral winter and summer seasons for the current and future climate. An automatic and objective method to monitoring specific features of meteorological fields of the "European Centre for Medium Range Weather Forecast"(ECMWF) and "National Centers for Environmental Prediction"(NCEP) reanalysis for the 1961 - 1990 and 1989 - 2008 periods and simulations of the "World Data Center for Climate"(WDC) for the 1961 - 1990 and 2071 - 2100 was applied in order to analyse statistics on the "Storm - Tracks"(ST) and show their interactions with low frequency ocean - atmospheric phenomena. The results show two marked cyclogenesis centers over the southeastern coast of SA and another one over the Antarctic Peninsula for both seasons on current days. It is noted that the austral summer ST is distributed in a latitudes range narrower than the cold season one and that the austral winter period presents higher ciclonic activity. It is diagnosed that the Antarctic Oscilation (AAO) or Southern Annular Mode (SAM) and the EI Niño Southern Oscilation (ENSO) signals influence the latitudinal position and mean intensities of relative vorticity in both seasons. Also MO is characterized as the principal mode of climate variability in middle and high latitudes. The climate projections results suggest that the ST belt displace towards high latitudes and the number of cyclones decreases in the future. The maximum baroclinic region shifts southwards and the influence of the SAM seems very important for the cyclonic activity redistribution of the future climate scenario.

ASSUNTO(S)

el niño southern oscillation extratropical cyclones climate change climatology climatologia oscilação antártica el niño oscilação sul ciclones extratropicais mudanças climáticas antarctic oscillation

ACESSO AO ARTIGO

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