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NASA News
National Aeronautics and Space Administration
Dryden Flight Research Center
P.O. Box 273
Edwards, California 93523
Phone   661-276-3449
FAX      661-276-3566                  
                                                                           
                                      

Frederick A. Johnsen, News Chief
NASA Dryden Flight Research Center
Phone: (661) 276-2998

April 14, 2003

Release:  03-22

NASA AND NAVAL RESEARCH LAB STUDY COASTAL EDDIES

Swirling waters off southern California will be studied by NASA and 
the Naval Research Laboratory (NRL) this month. These coastal eddies 
can be important in bringing nutrients from deep to surface waters 
where they provide stimulus for ocean plant growth. Eddies can 
transport pollutants that originated on land, recirculating this 
material for several days. This may have both good and bad 
consequences for life in the ocean.

Scientists from NASA's Jet Propulsion Laboratory and the Naval 
Research Laboratory, Washington, D.C., are interested in 
spiral-shaped slicks, or glassy water, on the ocean's surface that 
may result from small-scale eddies in the ocean. Theories predict the 
spirals take several days to evolve. These eddies are generally 
between three and six miles in diameter.

NASA will fly its specially-instrumented airborne sciences DC-8 jet, 
based at the Dryden Flight Research Center, Edwards, Calif., over the 
Southern California Bight, the area between Point Conception and San 
Diego, to locate eddies using Airborne Synthetic Aperture Radar 
(AIRSAR).

During daily flights, the AIRSAR, designed and built by NASA's Jet 
Propulsion Laboratory in Pasadena, Calif., will capture sequences of 
eddy images in rapid succession to enable researchers to measure the 
motion caused by currents. The DC-8 is vital to this project because 
it can be positioned with precision where needed over consecutive 
days.

"We can study the currents as they wind-up the ocean slicks into 
spiral patterns, and we can study the types of currents that either 
create or do not create eddies," said George Marmorino, coastal 
eddies lead scientist for NRL.

Once a clear ocean eddy is detected from the DC-8, the position of 
the eddy will be relayed to oceanographers on the Sea World UCLA, a 
research vessel that can measure the deeper currents and density 
structure associated with the eddy. Additional satellite imagery will 
also help to identify eddy locations.

While such small-scale eddies are common in the global coastal seas, 
surprisingly little is known about these eddies. The eddies' small 
size and transient nature have made it very difficult for ships to 
locate and measure their properties. Scientists hope the unique 
combination of the AIRSAR flights, ship measurements and satellite 
ocean sensors provide the best opportunity to understand the 
characteristics of these small but important coastal features. 
Collaborating in the study are the University of California, Los 
Angeles, departments of Civil and Environmental Engineering and 
Atmospheric Sciences and the Scripps Institution of Oceanography, 
University of California, San Diego.

For information about AIRSAR: http://airsar.jpl.nasa.gov;

For information about NASA's DC-8 flying laboratory:

www.dfrc.nasa.gov/research

For information about ocean coastal eddies: 

http://airsea-www.jpl.nasa.gov/cos/california/

- NASA -

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