This pair of Moderate Resolution Imaging Spectroradiometer (MODIS) images shows how fire activity increases over the course of a day as human agricultural activity increases. The morning overpass, taken by the Terra satellite on November 5, 2003, shows a few fires scattered across West Africa as red dots. The Aqua image, taken just five hours later, shows a band of dozens of fires. The daily increase in fire activity is called the diurnal fire cycle. The countries pictured in this image from the top right going clockwise are Mauritania, Mali, Guinea, Guinea-Bissau, Senegal, and Gambia.