Comparisons of chlorophyll variability between the four major global eastern boundary currents

Abstract

The first two years of SeaWiFS (Sea viewing Wide Field of view Sensor) data (1997–1999) are used to document the variability of large-scale surface chlorophyll patterns within the coastal region along the full latitudinal extent of each of the four major global eastern boundary currents; the California, Humboldt, Benguela and Canary Currents. Seasonal chlorophyll patterns are compared to coincident seasonal cycles of Ekman transport calculated from satellite scatterometer data. In all four regions, maximum chlorophyll concentrations are generally temporally and latitudinally coincident with the seasonal maximum in upwelling (offshore Ekman transport) over most of their latitudinal range, but exceptions are documented. Interannual differences are evident in each region, most notably in the two Pacific regions where the 1997–1998 chlorophyll seasonality was affected by El Niño conditions. Significant differences between previously published chlorophyll seasonality deduced from the relatively sparse coverage of the Coastal Zone Color Scanner (CZCS) and the more complete coverage of SeaWiFS in both Southern Hemisphere regions are evident.

Acknowledgments

Funding for ACT came from NASA grants NAG5-6558 and NAG5-6604 and NSF grants OCE-9711919 and OCE-0000899 (part of the US GLOBEC program). Funding for MEC was provided by the NASA Ocean Biogeochemistry Program and for PTS by JPL grant 958128 (TOPEX) and NASA grants NAG5-4947 (EOS) and NAG5-6604. GLOBEC contribution number 225.

Notes

An updated version of a paper originally presented at Oceans from Space ‘Venice 2000’ Symposium, Venice, Italy, 9–13 October 2000.