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Primary Productivity from MODIS Chlorophyll and Pathfinder SST
Program: NASA/NOAA Research and Operations Transition Program
Spacecraft: GeoEye Orbview-2, NOAA-POES, NASA Aqua
Sensor: Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on Orbview-2, Advanced Very High Resolution Radiometer (AVHRR) on NOAA Polar-orbiting Operational Environmental Spacecraft, Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua
Data Stream: Global area coverage for SeaWiFS, Global Area Coverage (GAC) for Pathfinder SST, Recorder LAC for MODIS
Primary Geophysical Parameter: Primary Productivity
Nominal Accuracy: unknown
Spatial grid: 0.1 degrees longitude by 0.1 degrees latitude, geographic
Spatial coverage: Global
Temporal Coverage: July 2002 - ongoing
FGDC Metadata Data Quality Act Documentation
NOAA CoastWatch provides a measurement of primary productivity based on the following satellite measurements: photosynthetically available radiation (PAR) values derived from the SeaWiFS sensor aboard the Orbview-2 satellite, chlorophyll-a concentration from the MODIS sensor on NASA's Aqua satellite, and SST measurements from the NOAA Pathfinder Project and from the Reynolds Optimally-Interpolated SST (OISST) v2 product from NOAA's National Climatic Data Center (NCDC). In the surface ocean, net primary productivity is the amount of organic carbon generated by photosynthesis in planktonic organisms minus the amount of organic carbon used by these organisms in respiration. Primary producers form the base of the food chain and generate the biomass that sustains all life in the ocean. NOAA CoastWatch Primary Productivity is an EXPERIMENTAL dataset, distributed for scientific evaluation.
The basic method used to calculate primary productivity follows Behrenfeld and Falkowski, 1997 . The calculation involves surface chlorophyll-a concentration from MODIS Aqua, temperature dependent photoadaptive variable used to determine the rate of photosynthesis from chlorophyll concentration, daylength, and an irradiance dependent function from SeaWiFS that measures how well light penetrates the water column.
Chlorophyll concentration is obtained from the MODIS/Aqua Chlorophyll-a product.
The photoadaptive variable is calculated using SST from two sources. For the monthly primary productivity product, SST is retrieved from the 0.1 degree monthly Pathfinder v5.0 SST product from NOAA's National Oceanographic Data Center (NODC). For the 8-day primary productivity product, SST is retrieved from the Reynolds Optimally-Interpolated SST (OISST) v2 product from NOAA's National Climatic Data Center (NCDC). Processing of the OISST product follows Reynolds et al., 2002.
Daylength is calculated from latitude and date-of-year following Forsythe et al., 1995.
The irradiance dependent function measures the amount of radiation avaiable to organisms for photosynthesis. It is the amount of radiation reaching the surface with wavelengths from 400-700nm. It is retrieved from the SeaWiFS Photosynthetically Active Radiation (PAR) product from NASA's Goddard Space Flight Center, OceanColor Web.
Data is mapped to an equal angle grid (0.1 degrees latitude by 0.1 degrees longitude) using a simple arithmetic mean to produce composite images of various duration (8-day 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 NOAA CoastWatch, NOAA NOS, and NOAA's NWS Monterey Regional Forecast Office.
References and suggested citations:
Behrenfeld, M.J., and P.G. Falkowski, 1997. A consumer's guide to phytoplankton primary productivity models. Limnol. Oceanogr., 42(7), 1479-1491.
Forsythe,W.C., E.J. Rykiel, R.S. Stahl, H. Wu, R.M. Schoolfield, 1995. A Model Comparison for Daylength as a Function of Latitude and Day of Year. Ecological Modelling. 80, 87-95.
Reynolds, R. W., N. A. Rayner, T. M. Smith, D. C. Stokes and W. Wang, 2002. An improved in situ and satellite SST analysis for climate. J. Climate, 15, 1609-1625.