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These Multi-angle Imaging Spectroradiometer (MISR) images from June 11, 2000demonstrate a turbulent atmospheric flow pattern known as the von Karman vortexstreet. This phenomenon is named after aerodynamicist Theodore vonKarman, who theoretically derived the conditions under which it occurs.The alternating double row of vortices can form in the wake of anobstacle, in this instance the eastern Pacific island of Guadalupe. Therugged terrain of this volcanic Mexican island reaches a maximumelevation of 1.3 kilometers. The island is about 35 kilometers long andis located 260 kilometers west of Baja California.
The vortex pattern is made visible by the marine stratocumulus cloudsaround Guadalupe Island. The upper image is a color view obtained byMISR's vertical- viewing (nadir) camera. North is toward the left. Theorientation of the vortex street indicates that the wind direction isfrom lower left to upper right (northwest to southeast). The areaswithin the vortex centers tend to be clear because the rotating motionsinduce a vertical wind component that can break up the cloud deck.
The lower view is a stereo picture generated from data acquired byMISR's fore- and aft-viewing 70-degree cameras. A 3-D effect is obtainedby viewing the image with red/blue glasses and placing the red filterover your left eye. Note how the downwelling atmospheric motion (changein elevation from high to low) is accompanied by a clearing in thecenter of the first vortex. As the vortices propagate downstream, theirrotational velocities weaken. As a consequence, the induced verticalmotion and cloud-clearing effect weakens as well.
Theodore von Karman was a Professor of Aeronautics at Caltech andDirector of Caltech's Guggenheim Aeronautical Laboratory from 1930-1949.He was one of the principal founders of the Jet PropulsionLaboratory.
Read Landsat 7Reveals Large-scale Fractal Motion of Clouds to learn more about Von Karmanvortex streets.
References & Resources
Image NASA/GSFC/JPL, MISR Team
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