UC Santa Cruz

A three stream irradiance model is implemented and tested to determine its utility for bio-geochemical data assimilation of remote sensing reflectance, Rrs(λ), data in the California Current System. Two different numerical methods were tested to solve the model, but the shooting method using a 4th order classical Runge Kutta scheme was implemented. The optical model solves for Rrs(λ) from the concentrations of variable optical constituents and their respective wavelength dependent light scattering and absorption properties. Using single phytoplankton type absorption and scattering estimates, the optical model produces Rrs values that correlate to satellite observed Rrs more closely for certain phytoplankton types than others. The model produced accurate downward irradiance fields when using observed absorption and scattering profiles obtained from the Ocean Observatories Initiative’s Oregon Shelf Surface Piercing Profiler Mooring. Through this forward modeling based comparison to observations it was found that the optical model can produce accurate profiles under certain conditions, making it promising for data assimilation of Rrs, but outstanding issues remain to be addressed, including accurately resolving community structure, improvements to the parametrization of constituents other than phytoplankton, and atmospheric influence on surface boundary conditions.