Abstract:
This data set consists of algorithm estimates of global Photosynthetically
Active Radiation (PAR) reaching the surface obtained by the Sea-viewing Wide
Field-of-view Sensor (SeaWiFS), in orbit on the OrbView-2 (formerly SeaStar)
platform. SeaWiFS data products are processed and distributed by the Ocean
Biology Processing Group (OBPG). Processing details can be found at
... http://oceancolor.gsfc.nasa.gov/DOCS/SW_proc.html
PAR is defined as the quantum energy flux from the Sun in the spectral range
400-700 nm. It is expressed in Einstein/m2/day. The PAR model uses
plane-parallel theory and assumes that the effects of clouds and clear
atmosphere can be de-coupled. The planetary atmosphere is therefore modeled as
a clear sky atmosphere positioned above a cloud layer. This approach was shown
to be valid by Dedieu et al. (1987) and Frouin and Chertock (1992). For
additional information about the algorithm see
http://oceancolor.gsfc.nasa.gov/DOCS/seawifs_par_wfigs.pdf
Each SeaWiFS Level-3 binned (9 km) data product consists of the accumulated
data for all Level-2 products, for the specified instrument and resolution,
corresponding to a period of one day, 8 days, a calendar month, a calendar
year, or the cumulative mission. The data are stored in a representation of a
global, equal-area grid whose grid cells, or "bins," have a resolution of
9.2x9.2km (approximately 81 km2).
Each given time binning period (Daily, 8-Day, Monthly, Monthly Climatology,
Seasonal, Seasonal Climatology, Annual, Cumulative) is stored in two HDF files.
These files include a main file containing all product-level metadata, and data
for each bin filled for that product and time period; and a subordinate file,
which contains the accumulated PAR data for all bins. Subordinate files must
be read in conjunction with the associated main file.
More detailed information on the Level-3 binned data product format
specifications can be found in the document at
http://oceancolor.gsfc.nasa.gov/DOCS/Ocean_Level-3_Binned_Data_Prod...
The SeaWiFS Level 3 Binned data files are available from the FTP site at
ftp://oceans.gsfc.nasa.gov/SeaWiFS/Binned/ 
