Sea surface temperature retrieval in tropical area with Meteosat: the case of the Senegalese coastal upwelling

Abstract

Many methods which are commonly used for sea surface temperature (SST) retrieval are frequently based on theoretical studies which may limit the needs of a real-time monitoring of hydro-climatic changes in the ocean. The method for SST retrieval described here, calls for a multi-temporal processing of data from the Meteosat series geostationary satellite coupled with the sea-truth measurements provided by ships of opportunity. In the Atlantic inter-tropical region, and especially in coastal areas, the method helps to obtain a very satisfactory monitoring on the important seasonal changes, with an easier and higher spatio-temporal resolution than other available methods. In this case the process of enrichment of coastal zones needs a detailed spatio-temporal description, leading to the choice of a more suitable time scale for studies of small spatial scale biological changes.An original preliminary SST climatology has been produced from Meteosat satellite data covering the 1984-1989 period of the upwelling season along the Mauritanian and Senegalese coasts. Its precision in coastal upwelling areas largely overcomes existing climatology and allows a precise calculation of SST anomalies. The real-time production of daily SST maps provides assistance for a local tuna fishery and has been used for this purpose in the tropical Atlantic Ocean at Meteo-France (Lannion, France) and at the University of Abidjan (Ivory Coast).

Effect of environmental conditions on the seasonal and inter‐annual variability of small pelagic fish abundance off North‐West Africa: The case of both Senegalese sardinella

“…As an alternative index of coastal upwelling, a monthly index of coastal SST was derived from the AVHRR Pathfinder product (1985–2009, NOAA, 4 km of resolution) for the Senegalese coast by averaging SST from the coast to the isobath 200 m where upwelling‐induced SST anomalies are generally maximum (Demarcq & Citeau, ). Alongshore winds generate coastal upwelling through offshore Ekman transport, which brings cold water from below the seasonal thermocline (50–200 m) to the surface, especially near the coast where the upwelling flow is at its maximum.…”

Application of a chlorophyll index derived from satellite data to investigate the variability of phytoplankton in the Benguela ecosystem

“…Monthly averages of sea surface temperature (SST) were produced to provide a description of the physical environment, by processing METEOSAT data (Demarcq and Citeau 1995) at a spatial resolution of 6km for the period September 1997 to December 2003 (data for 2004 were not available). The METEOSAT data has the advantage of offering a more efficient de-clouding procedure, thus providing a greater number of observations in the nearshore upwelling areas.…”

The importance of retention processes in upwelling areas for recruitment of Octopus vulgaris: the example of the Arguin Bank (Mauritania)

“…Satellite images of sea surface temperature (SST), received in the Oceanographic Research Centre of Dakar–Thiaroye from the European satellites of the METEOSAT series, were used to produce 5‐day synthesis maps of corrected sea surface temperature (Demarcq and Citeau, 1995). Spatio‐temporal variations in SST provide the main information about upwelling dynamics (Demarcq and Faure, in press).…”