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QuikSCAT Global Ocean Surface Wind Stress and Wind Stress Curl, Science Quality
Program: NASA QuikSCAT Winds
Spacecraft: Quick Scatterometer (QuikSCAT)
Data Stream: L2 Science Quality from Remote Sensing Systems Inc., Santa Rosa, CA
Primary Geophysical Parameter: Ocean Surface Wind Stress and Wind Stress Curl
Nominal Accuracy: ±0.01 Pa
Spatial grid: 0.25 degrees longitude by 0.25 degrees latitude, geographic
Spatial coverage: Global
Temporal Coverage: July, 1999 to Present
FGDC Metadata Data Quality Act Documentation
CoastWatch distributes wind velocity measurements derived from the Seawinds instrument aboard NASA's QuikSCAT satellite. The Seawinds instrument is a dual-beam microwave scatterometer designed to measure wind magnitude and direction over the global oceans. CoastWatch further processes these wind velocity measurements to wind stress and wind stress curl. These datasets are a precursor to other datasets that CoastWatch ditributes, Ekman current and Ekman upwelling. This is a Science Quality dataset, which is made available on a delayed time frame to allow for improvements in the data processing.
Data originates from the SeaWinds sensor on NASA's QuikSCAT satellite. The SeaWinds sensor is a dual-beam, rotating microwave scatterometer. The SeaWinds scatterometer bounces radar signals off the ocean surface and measures the strength of the returning backscatter signal. Wind roughens the ocean surface, which affects the backscatter signal and enables measurement of wind velocity. For information on how NASA processes the SeaWinds backscatter signal to wind velocity, see the QuikSCAT Global Ocean Surface Wind Velocity and Divergence Product.
CoastWatch processes wind velocities to wind stress following Smith, 1988 and to wind stress curl after the method of Gill, 1982.
Wind stress data are made available at 25km resolution in zonal wind stress (E-W direction), meridional wind stress (N-S direction), wind stress modulus (magnitude of wind stress), vectored wind stress, and wind stress curl products. All computations, including derivatives, are performed on the individual swath data, which are then mapped to an equal angle grid of 0.25 degrees latitude by 0.25 degrees longitude using a simple arithmetic mean to produce individual and composite images of various durations (e.g., 1, 3, 8, and 14-days, and monthly).
Despite our best efforts, incorrect data may often appear within near real time data sets. NOAA CoastWatch accepts no liability for use of these data products. It is recommended that these products NOT be used for navigation.
If this data is used for presentation or publication, please acknowledge the NOAA CoastWatch Program and the Remote Sensing Systems Inc.
References and suggested citations:
Gill, A.E., Atmosphere-Ocean Dynamics, International Geophysics Series, Vol. 30. Academic, San Diego, CA., 1982. pp326-328.
Smith S.D. 1988. Coefficients for sea surface wind stress, heat flux, and wind profiles as a function of wind speed and temperature. J. Geophys. Res., Volume 93, Issue C12, p. 15467-15472.