ARCTIC VORTEX STREET
NASA/GSFC/LaRC/JPL, MISR Team
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.
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 angls, 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.
dynamicist Theodore von Karman was the first to derive the conditions
under which these turbulence patterns occur. on Karman was a professor
of aeronautics at the California Institute of Technology and one of the
principal founders of NASA's Jet Propulsion Laboratory.
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.
credit: NASA/GSFC/LaRC/JPL, MISR Team. Suggested for inclusion in eFLuids
gallery by Dr. Zhou Yongcheng,
Department of Computational Science, National University of Singapore.