These MISR images from June 11, 2000 (Terra orbit 2569) demonstrate
a turbulent atmospheric flow pattern known as the von Karman vortex street.
This phenomenon is named after aerodynamicist Theodore von Karman, who
theoretically derived the conditions under which it occurs. The alternating
double row of vortices can form in the wake of an obstacle, in this
instance the eastern Pacific island of Guadalupe. The rugged terrain of this
volcanic Mexican island reaches a maximum elevation of 1.3 kilometers. The
island is about 35 kilometers long and is located 260 kilometers west
of Baja California.
The vortex pattern is made visible by the marine stratocumulus clouds around
Guadalupe Island. The upper image is a color view obtained by MISR's vertical-
viewing (nadir) camera. North is toward the left. The orientation of the
vortex street indicates that the wind direction is from lower left to upper
right (northwest to southeast). The areas within the vortex centers tend to be
clear because the rotating motions induce a vertical wind component that can
break up the cloud deck.
The lower view is a stereo picture generated from data acquired by MISR's
fore- and aft-viewing 70-degree cameras. A 3-D effect is obtained by viewing
the image with red/blue glasses and placing the red filter over your left eye.
Note how the downwelling atmospheric motion (change in elevation from high to
low) is accompanied by a clearing in the center of the first vortex. As the
vortices propagate downstream, their rotational velocities weaken. As a
consequence, the induced vertical motion and cloud-clearing effect weakens
as well.
Theodore von Karman was a Professor of Aeronautics at Caltech and Director of
Caltech's Guggenheim Aeronautical Laboratory from 1930-1949. He was one of
the principal founders of the Jet Propulsion Laboratory.
Image Credit: NASA/GSFC/JPL, MISR Team
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