In western Africa, the Sahara desert (top, in Mauritania) blends with a loosely defined strip of transitional vegetation to the south, called the Sahel (lighter green). South of the Sahel, tropical savannas begin to dominate (darker green). This true-color Moderate Resolution Imaging Spectroradiometer (MODIS) from the Aqua satellite shows fires (red dots) burning in the Sahel in northern Senegal (left center) and Mali (right center). To the south, fires are also burning in the savannas of Guinea. This image was acquired on November 9, 2002.
Compared to the Terra image acquired earlier in the day, more fires are visible; for example, notice the difference in western Guinea.