Includes bibliographical references.The coastal upwelling regions along northwest Africa (the Canary system), southwest Africa (the Benguela system), North America (the California system), and South America (the Peru-Chile system) were studied and compared on a seasonal timescale. A 17 -year NOAA Pathfinder Sea Surface Temperature (SST) dataset with a spatial resolution of 9km was used to describe the large-scale temporal and spatial variability of upwelling within the four regions. An upwelling index (OSST) was derived in order to add to the patterns of upwelling variability described from the sea surface temperature. The upwelling index was also used to describe the similarities and differences between the four upwelling regions. A 10-year ERS wind stress dataset with a spatial resolution of 10 x 10 was used to derive the offshore Ekman Transport in each of the regions. The offshore Ekman Transport was used to supplement the description of SST's in each system. Principal Component Analysis was used to investigate the variance structure of the anomalies of the sea surface temperature in each of the four regions. The results of the principal component analysis are interpreted in terms of the underlying physical dynamics
