Marine stratocumulus clouds frequently form parallel rows, or “cloud streets,”along the direction of wind flow. When the flow is interrupted by an obstaclesuch as an island, a series of organized eddies can appear within the cloudlayer downwind of the obstacle. These turbulence patterns are known as vonKarman vortex streets. In these images from NASA’s Multi-angle ImagingSpectroRadiometer, an impressive vortex pattern continues for over 300 km southward of Jan Mayen island. Jan Mayen is an isolated territory ofNorway, located about 650 km northeast of Iceland in the north AtlanticOcean. Jan Mayen’s Beerenberg volcano rises about 2.2 km above the oceansurface, providing a significant impediment to wind flow.
These MISR images were captured on June 6, 2001, during Terra orbit 7808. Theentire vortex street can be seen in the top panel, which is a natural-color viewfrom the instrument’s nadir (downward-looking) camera. The area covered measures365 kilometers x 158 kilometers, and a cloud-clearing effect is apparent at thevortex centers until finally closing on the sixteenth “hole.” The bottom panelis a stereo anaglyph of a portion of the vortex street, compiled using data fromMISR’s 26-degree forward and 70-degree backward viewing cameras. This viewcovers an area of about 183 kilometers x 96 kilometers. Despite the verticalexaggeration afforded by using widely separated angles, the relatively modestheight variation in the cloud layer implies a vertically stable atmosphere. Tofacilitate stereo viewing, the images have been oriented with north at the left.Red/blue glasses should be used with the red filter placed over your left eye.Information on ordering glasses can be found athttp://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses.
Fluid dynamicist Theodore von Karman was the first to derive the conditionsunder which these turbulence patterns occur. Von Karman was a professor ofaeronautics at the California Institute of Technology and one of the principalfounders of NASA’s Jet Propulsion Laboratory.
References & Resources
Image courtesy NASA/GSFC/LaRC/JPL, MISR Team
