Chlorophyll is an estimation of the concentration of the phytoplankton pigment, chlorophyll-a, at the lake surface and it is used as a proxy for the amount of phytoplankton in the surface water. This measurement has many applications for ecosystem modeling, fisheries management, and water quality monitoring.

The color-producing agents algorithm produces estimates of chlorophyll a, dissolved organic carbon, and suspended minerals through an optimization routine. It is based on a hydro-optical model developed for Lake Ontario (Bukata, et al., 1995) and is a combination of the Levenberg-Marquardt (L-M) multivariate optimization approach with a neural network (NN) emulation technique. The NN emulator provides the L-M procedure with reasonable initial constraints, which makes the final solution of the L-M procedure more accurate.

NOAA CoastWatch produces near real-time ocean color products, including chlorophyll, from the Moderate-Resolution Imaging Spectroradiometer (MODIS) on-board the NASA Earth Observing System (EOS) Aqua satellite and NOAA’s Advanced Very High Resolution Radar, Visible Infrared Imaging Radiometer Suite onboard the Suomi National Polar-Orbiting Partnership spacecraft (VIIRS S-NPP), NOAA-20 Visible Infrared Imaging Radiometer Suite (VIIRS NOAA-20).