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When the normal winds from the northwest along the Southern California coast are stronger
than normal, particularly during spring and summer, they interact with the local coastal
topography to form an atmospheric cyclonic vortex off Los Angeles, called Catalina Eddy.
The gentle winds of the Eddy may direct the offshore marine layer toward the Los Angeles
Basin. The cooling oceanic influence of the Eddy is often described as nature's purifier or
air-conditioner. The Eddy is only 100 km in diameter; it is actually too small to appear in the
present weather forecast models and is too shallow to have a strong influence on the cloud
structure viewed by weather satellites. The high resolution (12.5 km) capability of
QuikSCAT allows the visualization of the complete circulation of this "elusive' eddy. The
effect on the ocean is little known. Local ocean upwelling caused by such transient vortex is
often obscured by cloud cover and cannot be detected by operational Advanced Very High
Resolution Radiometer, and the wind field with sufficient resolution has not been available to
force realistic simulation by ocean general circulation model.
[From Liu, W.T., H. Hu, Y.T. Song, and W. Tang, 2001: Improvement of scatterometer wind
vectors - impact on hurricane and coastal studies. Proc. WCRP/SCOR Workshop of Airsea
Flux Validation, World Climate Research Programme, Geneva, in press]
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