Images
August 21, 2010 - Cloud vortices off Madeira and Canary Islands
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The steady south, southwest flow of bright white clouds on the Portuguese trade winds is dramatically interrupted by the island of Maderia and by the Canary Islands, resulting in swirls and eddies on the leeward side of each island. These swirls and eddies, known as Von Karman vortices, were captured on August 14, 2010 when the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite passed overhead.
Von Karman vortices are named after the fluid dynamicist and engineer, Theodore von Karman, co-founder of NASA's Jet Propulsion Laboratory, who first described the phenomenon. They occur when fluid flow is interrupted by a “bluff body”, which can be defined as a stationary object with a broad, flattened front. When moving fluid hits such an object, the fluid must part and flow around it. A quiet wake is formed immediately on the other side of the object but, as the fluid flows mix, turbulence forms in a symmetric and sometimes beautiful pattern. Mathematical formulations can be used to predict the pattern of the Von Karman vortices.
In the northeast corner of the image, the island of Maderia, Portugal, rises 1,862 meters (6,109 feet) above the ocean surface. On the day this image was captured, large fires were burning on the island and a wide plume of gray smoke can be seen trailing from the island, over the blue ocean waters and between the swirls of the vortices nearest the island. The smoke flows at a lower altitude than the clouds, and so does not become part of the Von Karman vortices.
South east of Maderia lies the Canary Islands, ten islands which are part of the Spanish Autonomous Community and are one of the outermost regions of the European Union. From largest to smallest the islands are: Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, El Hierro, La Graciosa, Alegranza and Montaña Clara. Compared to Maderia, the wakes on the leeward side are larger and the Von Karman vortices form a less distinct pattern.
Image Facts
Satellite:
Aqua
Date Acquired: 8/14/2010
Resolutions:
1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit:
Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC
The steady south, southwest flow of bright white clouds on the Portuguese trade winds is dramatically interrupted by the island of Maderia and by the Canary Islands, resulting in swirls and eddies on the leeward side of each island. These swirls and eddies, known as Von Karman vortices, were captured on August 14, 2010 when the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite passed overhead.
Von Karman vortices are named after the fluid dynamicist and engineer, Theodore von Karman, co-founder of NASA's Jet Propulsion Laboratory, who first described the phenomenon. They occur when fluid flow is interrupted by a “bluff body”, which can be defined as a stationary object with a broad, flattened front. When moving fluid hits such an object, the fluid must part and flow around it. A quiet wake is formed immediately on the other side of the object but, as the fluid flows mix, turbulence forms in a symmetric and sometimes beautiful pattern. Mathematical formulations can be used to predict the pattern of the Von Karman vortices.
In the northeast corner of the image, the island of Maderia, Portugal, rises 1,862 meters (6,109 feet) above the ocean surface. On the day this image was captured, large fires were burning on the island and a wide plume of gray smoke can be seen trailing from the island, over the blue ocean waters and between the swirls of the vortices nearest the island. The smoke flows at a lower altitude than the clouds, and so does not become part of the Von Karman vortices.
South east of Maderia lies the Canary Islands, ten islands which are part of the Spanish Autonomous Community and are one of the outermost regions of the European Union. From largest to smallest the islands are: Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, El Hierro, La Graciosa, Alegranza and Montaña Clara. Compared to Maderia, the wakes on the leeward side are larger and the Von Karman vortices form a less distinct pattern.
Image Facts
Satellite:
Aqua
Date Acquired: 8/14/2010
Resolutions:
1km ( B), 500m ( B), 250m ( B)
Bands Used: 1,4,3
Image Credit:
Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC
