Dust storm off West Africa

A large, swirling mass of dust, measuring several hundred kilometers across, was blowing from the Western Sahara over the Atlantic Ocean on September 4, 2005, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image. The dust storm covers almost the entire image, its color ranging from tan to pale beige. The islands at the top of the image are a part of the Canary Islands, a possession of Spain. The landmass on the right side of the image is North Africa, including the territory and country of Western Sahara (currently under the control of Morocco) and Mauritania, respectively.

Dust storms occur when very strong winds carry sand from the erg, or sand dune deserts, of the Sahara. Areas lacking vegetation, such as the Sahara, experience extreme daytime heat. This heat leads to turbulence in the lowest 1 to 2 kilometers of the atmosphere, known as the boundary layer. That turbulence can loft dust particles off the ground. So in places like the Sahara, dust storms result not only from abundant dust but also from conditions favorable to throwing the dust into the air.

Dust may .fertilize. the oceans and even the Amazon rain forest by carrying and depositing minerals over great distances. However, they are often exacerbated by agriculture practices that contribute to soil erosion- a process called desertification.

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Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC

Published September 7, 2005
Data acquired September 4, 2005

Source:

Terra > MODIS