Study of the atmospheric and oceanic conditions in the southweast atlantic and its relation with the Brazilian sardine catch extremes / Estudo das condições atmosféricas e oceânicas do atlântico sudoeste e suas associações com extremos de captura da sardinha-verdadeira

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The Brazilian Sardine is an important fishing resource for the country, with restricted occurrence in the Southeast Brazilian Bight (SBB). Landing records of this species shows years of high capture, as in 1973 with 225 thousand tons and the minimum in 2000 with 20 thousand tons. In this work was studied the oceanic and atmospheric characteristics of the most important spawning period, December and January, with the intention to investigate its possible relations with the catch extremes. The analysis was concentrated on relevant oceanic variables such as sea surface temperature, sea surface wind stress, Ekman transport and wind mixing index. The atmospheric variables investigated were precipitation, outgoing longwave radiation, wind and geopotential height. First, it was discussed the climatology of these variables for the period between 1970 and 2001. After the average atmospheric and oceanic behavior was investigated, the catch extremes were assessed. For that purpose it was selected the positive and negative years and calculated the average of variables and its anomalies. With this study was possible to identify that an excess of water mixing and surface transport in the north of SBB, during the spawning period is associated with low capture in the next year. This occurs because the excess of mixing and transport can to destroy food particles and could cause the dispersion of the eggs and larvae. An increase in the frequency of South Atlantic Convergence Zone and frontal systems over SBB, in the spawning period is associated with positive catch extremes. These systems can cause changes in the direction of winds in SBB, influencing the surface mixing and transport in the region.

ASSUNTO(S)

atmospheric and oceanic analysis compostos atlântico sudoeste sardinellea brasiliensis climatologia análise atmosférica e oceânica southwest atlantic climatology composites sardinella brasiliensis

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