Remote Sensing of African Lakes: A Review

The optical complexity and small size of inland waters make the application of remote sensing more challenging than for the open ocean. However, in Africa, where in situ monitoring of important water bodies is financially, institutionally and spatially constrained, there is strong demand for remote sensing to fill the critical information gap. Here we review a wide range of applications of both passive and active remote sensing to African lakes. The applications fall into five main categories: (1) visible, NIR, thermal and microwave sensing of lake area; (2) altimetric and gravimetric sensing of lake level; (3) thermal sensing of lake surface temperature; (4) visible, NIR and microwave sensing of macrophytes; and (5) optical sensing of trophic conditions including chlorophyll-a and euphotic depth. Sensors used include Landsat MSS, TM and ETM+, MERIS, MODIS, SeaWiFS, AVHRR, Meteosat, TOPEX/Poseidon, Jason-1, OSTM/Jason-2, ERS-1, ERS-2, Envisat, GFO, ICESat, ALOS-PALSAR and GRACE. The majority of studies have been applied to the "great" lakes such as Chad, Malawi, Tanganyika and Victoria; however, there is a growing body of literature on smaller lakes. We examine the possibilities that remote sensing offers to monitoring and management of African lakes as well as the potential limitations of the technology using Lake Victoria as an illustrative case.