Monitoring the Congo River Plume with the Oceanic currents derived from the AIS messages

The Congo river is the second most important river discharge in the global ocean after the Amazon river. The oceanic circulation in this near equatorial region plays a key role in the river fresh water advection into the Gulf of Guinea. Then, this circulation associated fresh water redistribution impact the Oceanic heat-content and the Ocean-Atmosphere exchange potentially influences the African climate. In this study, we focus in the river plume coastal region roughly located between longitude 10°E , 13°E and latitude 4.5°S, 7.5°S. We use a methodology to derive ocean surface current from the Automatic Identification System (AIS). The currents derived from the altimetry seem not able to represent the circulation in this area close to the equator and the coasts.. We show together with satellite data information of salinity (Sea Surface Salinity) and temperature (Sea Surface Temperature) that the AIS derived currents are able to monitor the dynamics of the River Congo plume and its seasonal cycle especially close to the coast. Using the vorticity of the flow we also highlight the consistency of the resulting circulation since few in-situ data are available in this region.