Abstract:
This data set consists of satellite measurements of global ocean color data
obtained by the Moderate Resolution Imaging Spectroradiometer (MODIS), in orbit
on the Aqua (formerly EOS PM) platform. MODIS ocean color products are
processed and distributed by the Ocean Biology Processing Group (OBPG).
Processing details can be found at
http://oceancolor.gsfc.nasa.gov/DOCS/MODISA_processing.html The
... Aqua MODIS Level 3 standard mapped image (SMI) products are integer
representations of binned data products. This image is an 8-bit,
two-dimensional array of an Equidistant Cylindrical projection of the globe.
(The capability to produce 16-bit SMI products has been implemented by the
OBPG, and the MODIS Ocean Color products are expected to be regenerated as
16-bits values at the next reprocessing in about 1 year.) Each SMI product
contains one image of a geophysical parameter and is stored in one physical HDF
file. The Level 3 binned products are used to generate mapped data products on
4 and 9 km equi-rectangular projection. The products are generated for the
following binning periods: Daily, 8-Day, Monthly, Monthly Climatology,
Seasonal, Seasonal Climatology, Annual, Cumulative.
Five SMI products are generated from each standard Ocean Color binned data
product, one for each of the following geophysical parameters:
-Chlorophyll-a concentration (CHLO)
-Normalized water-leaving radiance at band 5 (L551)
-Aerosol optical thickness at band 8 for atmospheric correction (T869)
-Angstrom coefficient, 531-869 nm, for atmospheric correction (A531)
-Diffuse attenuation coefficient at 490 nm (measure of optical clarity) (K490)
Each SMI product represents data binned over the period covered by the parent
product. The arithmetic mean is used in each case to obtain the values for the
SMI grid points from the binned data products.
More detailed information on the Level-3 Standard Mapped Image data product
format specifications can be found in the document at
http://oceancolor.gsfc.nasa.gov/DOCS/Ocean_Level-3_SMI_Products.pdf
Please, read the MODIS Ocean Parent document for more details:
http://gcmd.nasa.gov/getdif.htm?MODIS_OCEAN_PARENT 
