(W. Timothy Liu, Hua Hu, and William Patzert)

The detailed wind field measured by the scatterometer on NASA's QuikSCAT satellite mission reveals the elusive and, often welcome, Catalina Eddy.

When the normal winds blowing 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 counterclockwise 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 (60 miles) in diameter; it is actually too small to appear in the operational 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, near the coast.