Simultaneous retrieval of aerosol and coastal ocean properties by optimal estimation

We analyze Sea Viewing Wide Field-Of-View Sensor (SeaWiFS) images over the Santa Barbara Channel. Pixel-by-pixel measurements of radiances at 8 SeaWiFS channels and analytic Jacobians are simulated using a coupled atmosphere-ocean radiative transfer model. The retrival algorithm is based on optimal estimation with loosely constrained a priori data. The 5-element state vector has two aerosol (optical depth at 865 nm, bimodal fraction of particles) and three marine parameters (chlorophyll concentration, detrital/dissolved-matter absorption at 443 nm, and backscattering coefficient at 443 nm). The retrieval is stable and well posed; the results are smoother and show less spread than those derived from the standard SeaDAS v4.8 algorithm. Water-leaving radiances agree well with field measurements. The average radiance residual is less than 1% for 7 SeaWiFS channels, and less than 2% for the 765 nm channel.