Discoloured waters in the Melanesian Archipelago (New Caledonia and Vanuatu). The value of the NIMBUS-7 Coastal Zone Colour Scanner observations

Abstract

Final conclusions are given to the study of discoloured waters as they can be observed with the NIMUBS-7 Coastal Zone Colour Scanner (CZCS) in the oligotrophic waters of the southwestern tropical Pacific, in the Melanesian archipelago, around New Caledonia, Vanuatu (and Tonga). An attempt was made to define, in the four CZCS channels, the reflectance properties of these blooms attributed to Trichodesmium, a nitrogen-fixing cyanobacterium commonly found in that region. The capacity and limitations of the CZCS sensor used in the past as well as the SPOT imager are discussed in this respect. The usefulness of past and future ocean colour satellites in identifying zones of high chlorophyll concentration and bright linear patterns is demonstrated. -Author