Chad, from Desert to Sahel to Savanna12.8N 17.4E
Chad is divided into multiple regions: a desert zone in the north, an arid Sahelian belt in the centre and a more fertile Sudanese savanna zone in the south.
These changes in climate zone are easily observed in the image, which changes color from the yellow of the desert at the top, to the brown of the Sahel in the middle, to the green of the savanna at the bottom.
Visible by the left edge is Lake Chad, the largest wetland in the country and the second largest in Africa, although it is shallow and its size has varied over the centuries. According to the UN it shrank as much as by 95 percent from about 1963 to 1998 yet they also state that “The 2007 (satellite) image shows significant improvement over previous years”.
A smaller body of water, Lake Fitri, can be observed to the east of Lake Chad, in the center of the country. The normal size of the lake is about 50,000 hectacre. The size of this lake can triple in wetter years. This freshwater lake is shallow and is fed by seasonal rainfall and run-off from a catchment area estimated at 70,000 km². The principal river feed is the seasonal Batha River which carries water from the Ouaddai massif to the east.
Similar to Lake Chad, it is not quite as large as once was. It has been designated under the Ramsar Convention as a Wetland of International Importance. The normally permanent lake may dry out during severe drought periods, such as occurred at the beginning of the twentieth century and again in 1984–1985.