For these images, the aerosol optical depth and angstom exponent¹ are provided over ocean surfaces only and correspond to the values at 510 nm.

The algorithm uses an absorbing aerosol index² similar to the UV one for TOMS to help determine the kind of aerosol in the pixel. The optical depth and angstrom exponent is then calculated using an improved algorithm from the one used in the standard SeaWiFS products. The algorithm uses 36 different aerosol models (corresponding to dust, smoke, sea salt, sulfate, etc) to create reflectance tables. A table look-up technique is then used on those tables that match the aerosol characteristics indicated by the absorbing aerosol index to determine optical depth and angstrom exponent simultaneously. All 8 of the SeaWiFS channels are used, as opposed to the 2 used in the standard product. Fresnel reflection is assumed at the ocean surface.

These images were made using HRPT and GAC data provided by the SeaWiFS processing team.

¹ The angstrom exponent is known to be related to particle size; the larger the exponent, the smaller the particle size.

² The algorithm for determining absorbing aerosol index is currently being used in the operational processing of SeaWiFS data as a flag for absorbing aerosol. A description of it can be found in the appropriate SeaWiFS technical memorandum.