Remote Sensing Application for Monitoring Turbid River Plumes in the Gulf of Guinea

River plumes from major Nigerian rivers including the Niger, Benue, and Cross Rivers deliver enormous quantities of suspended sediment, nutrients, and pollutants into the Gulf of Guinea, with significant consequences for coastal water clarity, fisheries productivity, and coral reef health. This study applies remote sensing techniques to monitor the spatial extent, temporal dynamics, and turbidity characteristics of river plumes entering the Gulf of Guinea from Nigerian coastal rivers during 2022 to 2024. Daily MODIS Aqua true colour and shortwave infrared imagery are processed to derive surface reflectance products, from which a normalised difference turbidity index is computed and validated against in-situ turbidity measurements collected during three research cruises. Plume extent is digitised from cloud-free image composites at weekly intervals using a turbidity threshold algorithm. Seasonal composites depict the contrasting plume regimes during the dry season (reduced turbidity, clearer waters) and wet season (greatly expanded plumes driven by peak river discharge). The study investigates the role of the Guinea Current in dispersing the Niger Delta river plume along the Nigerian shelf and westward into Benin and Ghanaian coastal waters. Correlation analysis relates plume extent to upstream river discharge data from the Hydrology Department of the Niger Delta Development Commission. Findings are expected to demonstrate plume extents exceeding 50 kilometres offshore during October peak discharge events, with implications for offshore platform water intake quality and fisheries habitat disruption. Keywords: river plumes, remote sensing, Gulf of Guinea, turbidity, Niger Delta discharge