Wind Retention

a b s t r a c t Strengthening Western Boundary Currents (WBCs) advect warm, low nutrient waters into temperate lat-itudes, displacing more productive waters. WBCs also influence phytoplankton distribution and growth through current-induced upwelling, mesoscale eddy intrusion and seasonal changes in strength and pole-ward penetration. Here we examine dynamics of chlorophyll a (Chl. a) in the western Pacific Ocean, a region strongly influenced by the East Australian Current (EAC). We interpreted a spatial and temporal analysis of satellite-derived surface Chl. a, using a hydrodynamic model, a wind-reanalysis product and an altimetry-derived eddy-census. Our analysis revealed regions of persistently elevated surface Chl. a along the continental shelf and showed that different processes have a dominant effect in different locations. In the northern and central zones, upwelling events tend to regulate surface Chl. a patterns, with peaks in phytoplankton biomass corresponding to two known upwelling locations south of Cape Byron (28.5!S) and Smoky Cape (31!S). Within the central EAC separation zone, positive surface Chl. a anomalies occurred 65 % of the time when both wind-stress (sw) and bottom-stress (sB) were upwell-ing-favourable, and only 17 % of the time when both were downwelling-favourable. The interaction o