Dust off Western Africa

Dust off Western Africa

A plume of Saharan dust spanning hundreds of kilometers hovered over the eastern Atlantic Ocean in late July 2010. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image on July 25, 2010.

No obvious source points for the dust appear near the coast. The dust likely arose far inland, carried to the sea by the Saharan Air Layer—a hot, dry, dusty air mass that forms over the Sahara and travels over the Atlantic Ocean about every three to five days. This dust plume narrowly misses the Canary Islands in the north and Cape Verde in the south—two island chains regularly dusted with the Saharan sands. The plume’s trajectory, however, may carry some dust toward Cape Verde.

In the wake of the Canary Islands (just off the top edge of the image), vortices form in the clouds. The swirling paisley patterns follow a northeast-southwest path roughly parallel to that of the dust plume.

NASA image by Jeff Schmaltz, MODIS Rapid Response Team. Caption by Michon Scott.

References & Resources

  • Dunion, J. (2010, March 17). What is the Saharan Air Layer? Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration. Accessed June 26, 2010.