Marine stratocumulus clouds frequently form parallel rows,
or "cloud streets", along the direction of wind flow. When
the flow is interrupted by an obstacle such as an island,
a series of organized eddies can appear within the cloud
layer downwind of the obstacle. These turbulence patterns
are known as von Karman vortex streets. In these images from
NASA's Multi-angle Imaging SpectroRadiometer, an impressive
vortex pattern continues for over three hundred kilometers
southward of Jan Mayen island. Jan Mayen is an isolated territory
of Norway, located about 650 kilometers northeast of Iceland
in the north Atlantic Ocean. Jan Mayen's Beerenberg volcano
rises about 2.2 kilometers above the ocean surface, providing
a significant impediment to wind flow.
These MISR images were captured on June 6, 2001, during Terra
orbit 7808. The entire vortex street can be seen in the top
panel, which is a natural-color view from the instrument's
nadir (downward-looking) camera. The area covered measures
365 kilometers x 158 kilometers, and a cloud-clearing effect
is apparent at the vortex centers until finally closing on the
sixteenth "hole". The bottom panel is a stereo anaglyph of a
portion of the vortex street, compiled using data from MISR's
26-degree forward and 70-degree backward viewing cameras. This
view covers an area of about 183 kilometers x 96 kilometers.
Despite the vertical exaggeration afforded by using widely
separated angles, the relatively modest height variation in
the cloud layer implies a vertically stable atmosphere. To
facilitate 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 at
http://photojournal.jpl.nasa.gov/Help/VendorList.html#Glasses .
Fluid dynamicist Theodore von Karman was the first to derive
the conditions under which these turbulence patterns occur.
Von Karman was a professor of aeronautics at the California
Institute of Technology and one of the principal founders of
NASA's Jet Propulsion Laboratory.
MISR was built and is managed by NASA's Jet Propulsion Laboratory,
Pasadena, CA, for NASA's Office of Earth Science, Washington, DC.
The Terra satellite is managed by NASA's Goddard Space Flight Center,
Greenbelt, MD. JPL is a division of the California Institute of
Technology.
Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
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