|West Coast Regional Node|
Home | Information | Data | El Niño | Software | Sites | Feedback | About Us
Global Chlorophyll-a concentration from SeaWiFS
Program: NASA/GeoEye SeaWiFS Project
Spacecraft: GeoEye Orbview-2
Sensor: Sea-viewing Wide Field-of-view Sensor (SeaWiFS)
Data Stream: GAC
Primary Geophysical Parameter: Chlorophyll-a concentration
Nominal Accuracy: ±30%
Spatial grid: 0.1 degrees longitude by 0.1 degrees latitude, geographic
Spatial coverage: Global; 180°W to 180°E longitude, 75°S to 75°N latitude
Temporal Coverage: Sept, 1997 to present
FGDC Metadata Data Quality Act Documentation
NOAA CoastWatch distributes chlorphyll-a concentration for the global ocean from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on the Orbview-2 satellite. Because data is purchased under a NOAA contract with GeoEye, data distribution is restricted to authorized users. Chlorophyll images and data older than five years, however, are publicly accessible. Questions regarding data access should be directed to NOAA CoastWatch.
CoastWatch distributes ocean chlorophyll-a concentration images generated from the Sea-viewing Wide Field-of-View Sensor (SeaWiFS), an eight channel ocean color sensor on GeoEye's Orbview-2 satellite. Information on NASA's SeaWiFS project can be found on their OceanColor Web.
Data is downloaded and processed from the normalized water-leaving radiances to chlorophyll-a concentration using the NASA/GSFC SeaWiFS Project OC4v4 algorithm (e.g., O'Reilly et al., 1998; O'Reilly et al., 2000). NASA has also developed the SeaWiFS Data Analysis System (SeaDAS) software for the viewing, analysis, and processing of SeaWiFS and other ocean color data (Fu et al., 1998).
NOAA's validation of SeaWiFS data is accomplished by comparison with in situ chlorophyll-a concentrations gathered by research ships and buoys. NASA's validation efforts are carried out in a similar manner (Hooker and McClain, 2000).
SeaWiFS data is purchased under contract from GeoEye. Data distribution is restricted to US civilian government marine operational applications. Permissible data applications include stock assessment and harmful algal bloom monitoring. Data older than five years and SeaWiFS pictures, however, may be accessed without restriction. Questions regarding SeaWiFS data access should be directed to NOAA CoastWatch.
For authorized users, data is distributed at 10km resolution. Chlorophyll-a concentrations are accurate to within 30%. Data is mapped to an equal angle grid of 0.1 degrees latitude by 0.1 degrees longitude for the global ocean. The mapping uses simple arithmetic means to produce composite images of 8-day and monthly durations.
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, NASA's Goddard Space Flight Center, and GeoEye.
References and suggested citations:
Hooker, S.B., and C.R. McClain. 2000. The Calibration and Validation of SeaWiFS Data. Prog. Oceanogr., 45, 427-465.
Fu, G., Baith, K. S., and McClain, C. R. "SeaDAS: The SeaWiFS Data Analysis System", Proceedings of "The 4th Pacific Ocean Remote Sensing Conference", Qingdao, China, July 28-31, 1998, 73-79.
O'Reilly, J.E., Maritorena, S., Mitchell, B.G., Siegel, D.A., Carder, K.L., Garver, S.A., Kahru, M. and McClain, C. 1998. Ocean color chlorophyll algorithms for SeaWiFS. J. Geophys. Res., 103: 24, 937-24, 953.
O'Reilly, J.E., and co-authors, 2000. Ocean color chlorophyll a algorithms for SeaWiFS, OC2, and OC4: Version 4. In: SeaWiFS Postlaunch Technical Report Series, edited by Hooker, S.B and Firestone, E.R. Volume 11, SeaWiFS Postlaunch Calibration and Validation Analyses, Part 3. NASA, Goddard Space Flight Center, Greenbelt, Maryland. 9-23.