With its vast expanses of sand, framed by mountain ranges and exposed
rock, northwestern Africa makes a pretty picture when viewed from above.
This image was acquired by the Moderate-resolution Imaging
Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. The
Canary Islands can be seen on the left side of the image just off
Africa's Atlantic shore. The light brown expanse running through the
northern two thirds of the image is the Sahara Desert. The desert runs
up against the dark brown Haut Atlas mountain range of Morocco in the
northwest, the Atlantic Ocean to the west and the semi-arid (light brown
pixels) Sahelian region in the South.
The Sahara, however, isn't staying put. Since the 1960s, the desert has
been expanding into the Sahelian region at a rate of up to 6 kilometers
per year. In the 1980s this desert expansion, combined with over
cultivation of the Sahel, caused a major famine across west Africa. Over
the summer months, strong winds pick up sands from the Sahara and blow
them across the Atlantic as far west as North America, causing air
pollution in Miami and damaging coral reefs in the Bahamas and the
The white outlines on the map represent country borders. Starting at the
top-most portion of the map and working clockwise, the countries shown
are Morocco, Western Sahara, Mauritania, Senegal, Mali, Burkina Fasso,
Nigeria, Mali (again), and Algeria.
Image by Reto Stöckli, Robert Simmon, and Brian Montgomery, NASA Earth Observatory, based on data from MODIS