LONG-TERM GOAL

The goal of this effort was to incorporate extremely fast but accurate light calculations into coupled physical-biological-optical ocean ecosystem models as used for operational three-dimensional ecosystem predictions. Improvements in light calculations lead to improvements in predictions of chlorophyll concentrations and other water-quality parameters (such as visibility), and of upper-ocean thermal structure, relevant to naval needs. In particular, we wanted to imbed the EcoLight-S radiative transfer model in a three-dimensional, time-dependent, coupled physical-biological-optical ecosystem model and then use that coupled model to quantify differences in ecosystem biological and thermal development when using approximate vs. accurate optics. OBJECTIVES Currently available ecosystem models often use very sophisticated treatments of the hydrodynamics (e.g., primitive equation solutions in terrain-following coordinate systems to obtain the advection and upper-ocean thermodynamics and mixing), fairly sophisticated biology (e.g., primary production, nutrient utilization, and grazing in multi-component food webs), but use grossly oversimplified treatments of the optics. The optics component of coupled ecosystem models is sometimes just a single equation parameterizing the scalar irradiance or PAR (photosynthetically available radiation) i