Variabilidade espaço-temporal da clorofila-a e a relação com processos oceanográficos no Oceano Atlântico equatorial

Abstract

This paper describes the equatorial dynamics of regional process delimited by coefficients of determination R2. Ten years of Ocean color image data from SeaWiFS were used to investigate the variability within the Equatorial Atlantic. The sazonal and semi-annual features are estimated by harmonic analysis and these can be recognized along the equator, separating some regions by the known oceanographic structures. Equatorial and coastal upwelling, river discharges and retroflection of the NBC current are some of them. A description of six choosen pixels as representative of the regionality is presented and a link beetwen the principal processes is exploited. Two of them showed distinct features and presented characteristic periods of mesoescale variability like eddies, and dominant in the retroflection zone. It provides some information about the possible source of Tropical Instability Waves generated by barotropic instabilities. A Singular Value Decomposition was performed to quantify and confirm the sazonal and semi-anual features. The first three modes explains 47,8% of the total variability, where the first one shows annual signal. The second mode agree with the mean currents from OSCAR suggesting an effect of transport at the distribution of chlorophyll-a and the relationship with semi-annual behaviour.