noun, Pathology. 1. the accumulation of excessive ketones in the body, as in diabetic acidosis. Origin of ketosis. 1915-1920.
Climate zones of Africa, showing the ecological break between the hot desert climate of the Sahara Desert (red), the hot semi-arid climate of the Sahel (orange) and the tropical climate of Central and Western Africa (blue).
The combined conditions of an unstable marine and stable continental air masses result in an arid, tropical climate in the southern Sahara Desert. Average temperatures are lower here than in the north, particularly at higher elevations. In fact, the highest parts of the southern Sahara Desert get snow during winter. In the western section, the cold current from the Canary Islands creates humidity and fog, but reduces precipitation.