Um estudo observacional da formacao e trajetorias de anticiclones extratropicais na America do Sul / An observacional study of the extratropical anticyclones in the South American continent

AUTOR(ES)
DATA DE PUBLICAÇÃO

1991

RESUMO

In this study, South American extratropical anticyclones have been studied in the period between 1979 and 1989 for the weak and moderate ones and between 1953 and 1990 for the most intense ones (in which average pressure was greater or equal to 1030 hPa) by using daily synoptic charts. The main goal of this work was to show the tracks of the anticyclones and the regions where the first closed isobar appeared more frequently in the area between 15° S and 55° S over the South American Continent. Initially we estimated the number of days in which inner anticyclonic curved isobars crossed the 5 x 5 degrees areas. Then all tracks of the migratory anticyclones were followed by using daily surface charts. The highest pressure located in the interior of the anticyclones or ridges and temperature was interpolated. We concluded that orography plays an important role in the distribution of anticyclonic isobars, with a higher number of days to the west of the Andes cordillera than to the east of the moutains. It was observed that the anticyclogenetic area for the moderate and weak ones is located in an area to the south of Paraguai and North Argentina, while the most intense ones have their first closed isobar in central Argentina. The weak anticyclones follow a zonal track and the moderate or intense ones follow a path oriented in the SW-NE direction.

ASSUNTO(S)

climatology climatologia meteorologia dinamica anticiclones dynamic meteorology anticyclone

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