Atmospheric and advective forcing of upwelling on South Africa's central Agulhas Bank

Current and temperature structures on South Africa's central Agulhas Bank are described from six months of moored observations ancillary data collected during the seasonal transition austral spring to summer (October 2018–March 2019). The occurrence an intermittend mid-shelf upwelling ridge, associated with increased productivity, is important part shelf's thermal structure. However, subsurface evolution this cold ridge has not been documented date. A mooring array that transected wide shelf captured increase in stratification culminated formation a late summer. We show originates wind-driven zone eastern emphasise importance oceanic forcing maintaining structure through advective steering coastal plumes dynamic edge upwelling. main source basal layer at transect originated further east, but persistent near-seabed temperatures <9 °C outer encroachment confirm contribution upwelling, offshore transect, bottom Bank. Of particular interest strengthening south-westward current, inshore cyclonic flow Bight accelerated advection productive water shape ridge. circulation be highly coherent across along shelf. Shelf-wide barotropic pulses were driven by zonal wind stress was turn variation sea level. In light global climate change, work highlights long term in-situ monitoring understanding ecosystem functioning