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QuikSCAT Global Ekman Current Velocity and Ekman Upwelling, Science Quality
Program: NASA QuikSCAT Winds
Spacecraft: Quick Scatterometer (QuikSCAT)
Data Stream: L2 Science Quality from Remotes Sensing Systems, Inc. of Santa Rosa, CA
Primary Geophysical Parameter: Ekman Current and Ekman Upwelling
Nominal Accuracy: unknown
Spatial grid: 0.25 degrees longitude by 0.25 degrees latitude, geographic
Spatial coverage: Global
Temporal Coverage: July, 1999 - 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, and finally to 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 we process the SeaWinds backscatter signal to wind velocity, see the QuikSCAT Global Ocean Surface Wind Velocity and Divergence Product. CoastWatch further processes this wind velocity to Wind Stress and Wind Stress Curl.
CoastWatch processes wind stress fields to Ekman current, the horizontal movement of surface water in response to wind stress, and Ekman upwelling, the vertical movement of water as a result of horizontal water movement at the ocean surface. These data are calculated after Pond and Pickard, 1983.
Ekman current and upwelling are made available at 25km resolution in zonal current (E-W direction), meridional current (N-S direction), current modulus (magnitude of current), vectored current, and Ekman upwelling products. The data are 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 Remote Sensing Systems Inc., of Santa Rosa, CA.
References and suggested citations:
Pond, S. and G.L. Pickard. 1983. Introductory Dynamical Oceanography. 2nd Edition. Butterworh- Heinemann Ltd. Oxford UK. Pp. 109-111.