Images
May 15, 2023 - Swirling Clouds off of Western Africa
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Fanciful patterns frequently form in the clouds off of western Africa and the twists and twirls are easily viewed from space. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a true-color image of multiple lines of vortices spinning across the clouds behind the Canary Islands and Madeira Island on May 12, 2023. Madeira is north of the Canary Islands and has a longer design trailing towards the southwest behind it.
These cloud patterns—known as von Kármán vortices—are a familiar atmospheric phenomenon, especially in areas where trade winds are prevalent. Physicist Theodore von Kármán, a co-founder of NASA’s Jet Propulsion Laboratory, was the first to describe the physical processes that create these chains of spiral eddies.
Von Kármán vortices can form nearly anywhere that fluid flow—including an air mass, as shown here—is disturbed by a solid object. In this case, winds blowing across the ocean are disturbed by small but tall islands that poke above the surface of the North Atlantic. The air mass, and clouds moving with it, blows around instead of over the island, creating winding, twirling patterns from the turbulent air flow behind the islands. The shape and length of the patterns depend on several factors, including wind speed, cloud cover, and shape of the object blocking the flow of the wind.
Image Facts
Satellite:
Terra
Date Acquired: 5/12/2023
Resolutions:
1km (2.3 MB), 500m (6.4 MB), 250m (5.4 MB)
Bands Used: 1,4,3
Image Credit:
MODIS Land Rapid Response Team, NASA GSFC
Fanciful patterns frequently form in the clouds off of western Africa and the twists and twirls are easily viewed from space. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired a true-color image of multiple lines of vortices spinning across the clouds behind the Canary Islands and Madeira Island on May 12, 2023. Madeira is north of the Canary Islands and has a longer design trailing towards the southwest behind it.
These cloud patterns—known as von Kármán vortices—are a familiar atmospheric phenomenon, especially in areas where trade winds are prevalent. Physicist Theodore von Kármán, a co-founder of NASA’s Jet Propulsion Laboratory, was the first to describe the physical processes that create these chains of spiral eddies.
Von Kármán vortices can form nearly anywhere that fluid flow—including an air mass, as shown here—is disturbed by a solid object. In this case, winds blowing across the ocean are disturbed by small but tall islands that poke above the surface of the North Atlantic. The air mass, and clouds moving with it, blows around instead of over the island, creating winding, twirling patterns from the turbulent air flow behind the islands. The shape and length of the patterns depend on several factors, including wind speed, cloud cover, and shape of the object blocking the flow of the wind.
Image Facts
Satellite:
Terra
Date Acquired: 5/12/2023
Resolutions:
1km (2.3 MB), 500m (6.4 MB), 250m (5.4 MB)
Bands Used: 1,4,3
Image Credit:
MODIS Land Rapid Response Team, NASA GSFC
