Changes in coastal upwelling in the northern Gulf of Guinea under Stratospheric Aerosol Injection

In the context of global warming, boreal summer upwelling intensity decreases all along the coast by 6% (with 2% in the Cote d'Ivoire region and a more significant decrease of 10% in the Ghana region). This decrease in upwelling intensity is linked to the intensification of geostrophic flow towards the coast. Under SAI, coastal upwelling intensity is still decreased by 5% along the coast (with 3% in the Cote d'Ivoire region and 6% in the Ghana region), but this decrease is relatively weak compared to global warming.

This increase in upwelling intensity compared with climate change, especially in Ghana, is associated with a 50% reduction in the effect of geostrophic flow limitation with respect to global warming. During the minor upwelling season, the upwelling intensity increases, due to Ekman transport, both under the climate change and SAI.