A GIS development for the study of coastal and open-sea upwellings is presented in this paper. Pollings is presented in this paper Remotely sensed sea surface temperature (SST), wtnd data (WD. remotely-sensed and measured), and bathymetric contours are used to identify upwellings, measure mean SST inside and outside the upwelling patches caIcula e upwellmg area, duration, grayity center, and track grayity center moyement of subsequent^Terns' GIf de''''°P"’ent is called Upwellmg Identification and Measurement System (UPWELL) and feaSS a complete user-mterface. UPWELL is applied in two different upwelling sea areas of Greece one Ξ coastal upwellings (North Aegean Sea) and another with open-sea upwellings (West Cretan Sea) bpwelta indices for these areas are presented from 1993-95 (North Aegean Sea) and 1993-97 (West Cretan Seal in ? weekly resolution. TTte GIS-based UPWELL system works in three surges: The upwellta™ L identified from an SST image, they are yerified by wind data according to upwelling theory, and Sly thS are measured and tracked into upwelling index reports. The use of GIS in this study proved ideal becaus- GIS integrated multi-year SST and WD data in a set of interfaced routines.