The Guinea Stream is a slow warm water current that moves eastward along West Africa's Guinea coast. Off the western coast of Africa, near the Gulf of Guinea, the Guinea Circulation is an Atlantic Ocean surface oceanic current that is the eastward continuation of the Atlantic Equatorial Countercurrent.

Here is the link to the Ocean Salinity data source covering the Gulf of Guinea

https://podaac.jpl.nasa.gov/SeaSurfaceSalinity

I would like to recommend reading the following papers:

1- Seasonal Variations in Temperature and Salinity in the Gulf of Guinea (medcraveonline.com).

2-https://medcraveonline.com/JAMB/seasonal-variations-in-temperature-and.

Most of the oceanic & meteorology you can find here, I hope this is useful

APDRC platform http://apdrc.soest.hawaii.edu/data/data.php?discipline_index=2

https://www.ncei.noaa.gov/metadata/geoportal/rest/metadata/item/gov.noaa.nodc%3A0108087/html