ABSTRACT
Laterite cappings in West Africa are thin-soiled and provide poor drainage conditions. It has been used with reference to both north-easterlies and to the equatorial easterlies, although the latter are generally associated with the lowest temperatures and the densest dust haze. Rainfall is provided by moisture from south-westerly mE airstreams and is at its heaviest at the point of maximum instability in the zone of contact between north-easterly and south-westerly air. Frontal disturbances are the most important factor in producing rainfall in West Africa and the movement of the ITC must be understood to appreciate the distribution of precipitation and, to some extent, of temperature. Natural grasslands may occur in areas of seasonal flooding or on cappings of impermeable material such as laterite, wherever soils are thin and drainage poor. On its northern margins the moist forest has been degraded into the greatest extent of open perennial grassland in West Africa.
