Watermasses, currents and tides at the Sofala Bank, November 1987

The southern part of the Sofala Bank (in Mozambique) was investigated. A net of closely spaced hydrographic stations were obtained and a current meter mooring consisting of two current meters and a bottom pressure recorder was deployed. High salinity shelf water was observed near shore with a maximum salinity above 36.6 ppt. Both average and tidal currents are discussed. The mean currents are steered by the continental slop and seem to be influenced by the wind. The tides have strong semidiurnal components, with a major axis of 53 cm/s perpendicular to the coast at 60m depth. The possibility that the tides may transport passive drifters with a diurnal vertical migration pattern up to a few kilometers a day is considered

Elementos basicos de teledetecção. Possibilidades da sua aplicação na investigação pesqueira em Moçambique

Mozambique has a large Exclusive Economic Zone (EEZ). Satellite remote sensing combined with ground observation would help in the research undertaken for fisheries purposes. NOAA could be applied for sea surface temperature mapping of the open sea water as the thermal gradient is high enough here. Coastal zone dynamics would be remotely sensed by visible passive radiance, since colour contrast is here the relevant pattern. Landsat/MSS seems to be economically advantageous for this purpose. This knowledge would contribute to locate the areas adequate for the concentration of fisheries resources

Detecting the Zambezi River plume using observed optical properties

In April 1998 a research cruise was carried out in the Mozambique Channel taking detailed optical, water quality and salinity measurements; the Zambezi plume waters were apparent through strong colour fronts with green waters in the plume and clear blue waters offshore. A good (r2=0.76) negative empirical relationship was found between the salinity (S) and yellow substance, represented by the absorption of filtered samples at 440 nm (g440). An empirical relationship was found between the salinity and a reflectance ratio: An optical model in which light absorption is dominated by yellow substance and light scattering by inorganic particles confirms this empirical relationship. This has been applied to a SeaWIFS image to map salinity on the Sofala Bank, demonstrating the potential to remotely determine the distribution of the Zambezi River plume. It is thought that any significant level of chlorophyll would reduce the effectiveness of the above algorithm