Abstract
A mesosoale study was made of the Ilha Grande area. The local circulation described through -progressive vector diagrams showed a clochwise bottom circulation determined in June 1976, while in the upper 10 m the direction of the flow entering the Ilha Grande Bay was towards the center in the west and towards the Marambaia sandbank in the east side of the Bay. Short periods and amplitude fluctuations were evaluted using power spectral analysis, Fourier and Maximum Entropy Method, which showed that in the upper 10 m predominant periods decrease from 1.1h (A = 6.3cm sec-1) (position = 3C) to 1.0h (A = 7.4 cm sec-1) (position = 2D) and increase to 5.8h (A = 6.8 cm., sec-1) (position = ID), while at the bottom layer the predominant period increases from 0.4 h (A = 5.0 cm sec-1) (position = 3G) to 6.4h (A = 7.0 cm sec-1) (position = 2G) and to 4.4h (A = 7.9 cm sec-1) (position = 1G) . From the original data it has been possible to determine an "intense pulsation" between 30-70 cm sec-1 in the upper 10 m with about 1.0h period and 10-20 min duration in all the stations.
ARTIGOS
Determination of circulation and short period fluctuation in Ilha Grande Bay (RJ), Brazil
Yoshimine Ikeda; Merritt Stevenson* * Instituto de Pesquisa Espacias Avenida dos Astronáutas, 1758 - Caixa Postal 515, 12.200 - São José dos Campos, São Paulo.
Instituto Oceanográfico da Universidade de São Paulo
SYNOPSIS
A mesosoale study was made of the Ilha Grande area. The local circulation described through -progressive vector diagrams showed a clochwise bottom circulation determined in June 1976, while in the upper 10 m the direction of the flow entering the Ilha Grande Bay was towards the center in the west and towards the Marambaia sandbank in the east side of the Bay. Short periods and amplitude fluctuations were evaluted using power spectral analysis, Fourier and Maximum Entropy Method, which showed that in the upper 10 m predominant periods decrease from 1.1h (A = 6.3cm sec-1) (position = 3C) to 1.0h (A = 7.4 cm sec-1) (position = 2D) and increase to 5.8h (A = 6.8 cm., sec-1) (position = ID), while at the bottom layer the predominant period increases from 0.4 h (A = 5.0 cm sec-1) (position = 3G) to 6.4h (A = 7.0 cm sec-1) (position = 2G) and to 4.4h (A = 7.9 cm sec-1) (position = 1G) . From the original data it has been possible to determine an "intense pulsation" between 30-70 cm sec-1 in the upper 10 m with about 1.0h period and 10-20 min duration in all the stations.
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Acknowledgements
The basic data processing and preparation of this paper was supported by OAS (Programa Multinacional de Ciências do Mar) , "Projeto Integrado para Uso e Exploraçao Racional do Meio Ambiente Marinho", subprojetos Biologia da Pesca e Hidrodinâmica Costeira - FINEP". The Inter-American Tropical Tuna Commission provided computer programs for the subsequent tine series analysis of current meter time series. Our thanks to Prof. Afrânio Rubens de Mesquita, for guidance in using Maximum Entropy Method programmes, and interpreting the results; to Mrs. Maria Cecilia Catunda, for the revision of the English manuscript; to Mr. Marco Antonio Montalban, for the drawings and to Miss Marilza Correia, for typing the manuscript.
(Received in 21/May/1979)
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Publication Dates
-
Publication in this collection
04 June 2012 -
Date of issue
1980
History
-
Received
21 May 1979
