Seasonal Variability of Freshwater Plumes in the Eastern Gulf of Guinea as Inferred From Satellite Measurements

In the eastern Gulf of Guinea (GG), freshwater originated from rivers discharges into ocean and high precipitation rate are key contributors to upper vertical density stratification, play a role in modulating local air-sea interactions as well biogeochemical cycle. Nevertheless, dynamics GG plumes remain poorly documented because scarcity historical, situ observations lack an ad hoc satellite-based analysis this region. Recent advances remote sensing capabilities Soil Moisture Ocean Salinity (SMOS) satellite mission offer unprecedented coverage spatiotemporal resolution Sea Surface (SSS) GG. Using SMOS SSS available measurements, seasonal variability associated physical mechanisms controlling their cycle presented analyzed. Freshwater follow two dynamical regimes. They present maximum offshore extension during boreal winter exhibit minimum signature summer. northeastern GG, is mainly explained by Niger River runoff winter, while late summer, driven horizontal advection. contrast, southeast supplied Congo runoff. From September March, zonal advection, with major contribution Ekman wind-driven currents. During spring-summer, observed increase likely entrainment mixing. budget advection processes discussed context shallow stratification induced freshwater.