Atmospheric correction over case 2 waters using an iterative fitting algorithm including relative humidity

It is generally assumed that the spectral variation of aerosol optical depth is characterize by an Angstrom power law or similar dependence. In an iterative fitting algorithm for atmospheric correction of ocean color imagery over case 2 waters previously described, this leads to an inability to retrieve the aerosol type and the attribution of spectral effects due to the water contents to aerosol spectral variations. An improvement to this algorithm is described in which the spectral variation of optical depth is calculated as a function of aerosol type and relative humidity, and the relative humidity is retrieved as well as aerosol type. The aerosol is treated as a mixture of aerosol components, rather than of aerosol types. We demonstrate the improvement over the previous method by using simulated case 1 and case 2 SeaWiFS data.