Principais sistemas sinópticos que atuaram sobre a Península Antártica no verão de 2001/2002 e a circulação troposférica associada / The main synoptic system that effected the Antartic Peninsula in the 2001/2002 summer and the associated tropospheric circulation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The behaviour of synoptics systems which affected the Antarctica Peninsula and Drake Passage during the Operantar XX, in the 2001/2002 summer, were analysed in this study. Three main methods were developed. The first one, is to evaluate the behaviour of the large and mesocyclones which occurred in the area, during december, january and february, using satellite images. A statistical analysis was performed, related to the size, displacement and development of the systems. The passage of cyclones over the area occurs in one or two days. The cyclones with complete lifecycle were the dominant cases and northwest was the dominant direction of the systems arriving in the region. It was noticed that the Bellingshausen Sea is the main area of the decaying large systems, and also of the origin of new small scale vortices. In the second method, extreme cases of wind and pressure, in the Antarctica Peninsula, were identified analysing the data obtained at the Antartica Station Comandante Ferraz. These occurrences were discussed considering the behaviour of the synoptic systems in the region. There is not a large change in temperature at the surface associated with the passage of the cyclones, and the reduction or increase of temperature depends on the direction of the propagation of the systems. High relative humidity in the area is permanent in the summer. Some cases from the satellite images study and the station data study were selected, following the third methodology, to analyse the atmospheric fields at low and high levels. The selected cases were taken considering the systems with intense cyclonic development, low pressure and strong winds. The presence of the systems were associated with strong temperature advection in the atmospheric circulation at low and high levels. Analyses from the weather forecast guidance from the AGCM CPTEC/COLA, for three selected cases, indicated that the atmospheric fields were reasonably well forecasted.

ASSUNTO(S)

vorticidade umidade atmosférica atmospheric moisture atmospheric general circulation models (agcms) atmospheric heat budget balanço de calor atmosférico modelos de circulação geral da atmosfera. key words: vorticity fontes de calor heat sources

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