Mesoscale eddies and high chlorophyll concentrations off central Chile (29 degrees-39 degrees S)

摘要

The offshore propagation of mesoscale eddies contributes significantly to expanding the area of high chlorophyll concentration beyond the coastal upwelling center as shown by satellite data of chlorophyll, wind stress, sea level anomalies between ( 1997 - 2003) off central Chile. Mesoscale eddies ( similar to 6.45 x 10(3) km(2)) formed near the coastal zone in spring-summer have mean seaward speeds of similar to 1.68 km d(-1) and reach similar to 500 km offshore in winter. Chlorophyll concentrations along eddy paths are elevated by nutrient pumping and by nutrients and/or chlorophyll transported from the coastal zone. Eddies make up > 50% of the winter ( weak upwelling) chlorophyll peak in the coastal transition zone. Coupling between eddies and upwelling extends central Chile's high productivity area offshore and prolongs it towards winter.