Summary of Abstract Submission

Abstract Submission No. IO50-04-0012PresentationPoster


Heriniaina Juliano Dani RAMANANTSOA*1

1 Fisheries and Marine Science of Madagascar (IH.SM), MADAGASCAR


The coastal upwelling regions south of Madagascar is renowned for its high productive marine ecosystems which sustains large biological food web. However, this ecosystem is a highly variables phenomena which can have a vital effects on the fluctuation of the trophic dynamics. Very high resolution satellite data is used to investigate seasonal and annual variability of the coastal upwelling south Madagascar. The research is aimed to understand the variability in order to understand the change in the past, to the present and for the future. The spatial dynamic of the upwelling cell is made in evidence by using Multi-scale Ultra-high Resolution (MUR), new generation of Sea Surface Temperature (SST) product. The upwelling has two seasonal cores which have different properties. Upwelling indexes were calculated to qualify and quantify the intensity of the upwelling event for each core. Revealed as a permanent upwelling, its higher intensity is mostly occurred during austral winter season. Upwelling index spectral analysis has shown an important energy in annual cycle and more than 80 percent of the total of the variance indicated the explanation of the timescale seasonality. Spatial correlation has been significantly favorable between upwelling index and chlorophyll-a concentration. A lag correlation approach between both was showed that the biological response is observed after less one month since an upwelling event. Physical processes responsible of the upwelling event are examined. The combination between EMC and favorable wind have influenced mostly the process generating the upwelling event