In Northern Africa, the Sahara Desert transitions into asemi-arid zone of grass and scattered shrubby vegetation known as the Sahel.Farther south, the Sahel turns into more thickly vegetated savanna. Forthousands of years, African farmers and herders have set fires in these regionsto manage natural resources, for example, to clear brush, to stimulate newgrowth of pasture grasses, or to drive game. These continent-spanning firesoccur in different seasons, depending on the latitude. This image from theModerate Resolution Imaging Spectroradiometer (MODIS) on NASAs Aqua satellite captured onNovember 20, 2006, captures the northern Africa fire season fully underway.Hundreds, possible thousands, of active fires that MODIS detected are markedwith red dots. The fires span countries all the way across Africa from theAtlantic Ocean (image left) to the Red Sea (upper right). Although these firesare not necessarily immediately hazardous, such large-scale burning cannevertheless have a strong impact on weather, climate, human health, and naturalresources.
20 November 2006
The spottier vegetation of the Sahel has a dull, faint brownish-greenappearance, while the savannas appear darker green. The dark-colored rocks thatcrop up out the sands of the Sahara Desert document the regions volcanic past.In the center of the image, a bright plume of dust whisks west-southwest fromthe Bodele Depression, one of the world’s single largest sources of dust.Southwest of the depression, a bright green patch is vegetation growing in andaround Lake Chad. The haze farther west of the lake may be a mixture of smokeand dust. This image was made from three successive overpasses of the Aquasatellite over North Africa. The white strips in the scene are the gaps betweenswaths.
The high-resolution image provided above has a spatial resolution of 1kilometer per pixel.