The relation of wind-driven coastal and offshore upwelling in the Benguela Upwelling System

Abstract Spatial and temporal variations of nutrient-rich upwelled water across the major eastern boundary upwelling systems are primarily controlled by surface wind with different, sometimes contrasting, impacts on coastal driven alongshore offshore local wind-stress-curl. Here, concurrently measured wind-fields, satellite-derived Chlorophyll-a concentration along a state-of-the-art ocean model simulation spanning 2008-2018 used to investigate connection between physical drivers Benguela Upwelling System (BUS). Our results indicate that spatial structure long-term mean derived from Ekman theory numerical fairly consistent entire BUS closely followed pattern. The variability is proportionally diminished distance, whereas different opposite structures revealed in model-derived upwelling. result suggests presence sub-mesoscale activity (i.e., filaments eddies) large modulating effect wind-stress-curl-driven off Lüderitz Walvis Bay. In Kunene Cape Frio cells, located northern sector BUS, open-ocean frequently alternate each other, they modulated annual cycle mostly phase Such relationship appears be strongly seasonally dependent southern BUS. Thus, our findings suggest this far more complex than currently thought seems sensitive climate changes short- far-reaching consequences for vulnerable marine ecosystem.