All quantities are functions of wavelength.
The absorption by phytoplankton can be specified in a number of ways, but all are essentially a spectral shape and some sort of chlorophyll dependency. The value of A and B can be supplied in a file, or can be taken from published liturature. The value of a CDM can be determined either as a function of chlorophyll concentration, or based on specified absorption at a reference wavelength. The coefficient S is defaulted to 0.014, but can be specified. Potentially, other types of in-water constituents which have different spectral signitures will be added in the future.