Application of a generalized Green’s function approach to optimize modeled tidal and tidal residual currents for assessment of the dispersion area of thermal effluent discharges

ABSTRACT This paper proposes a generalized Green’s Function Approach (GFA) to calibrate the boundary conditions and parameters of a coastal current model. The GFA uses a pseudoinverse for the calculation of control variables, including the boundary conditions and parameters, and a Green’s function matrix, which is the response matrix of sensitivity experiments to the control variables. The GFA was applied to optimize tidal and tidal residual currents in a coastal region with a model simulating the thermal effluent discharged from a power plant. The GFA could be used robustly, regardless of the number of sensitivity analyses, and provided optimal increments for the control variables using a given threshold for the pseudoinverse. The optimization provided the appropriate sea surface conditions to reproduce tidal and tidal residual currents that were consistent with observations. The optimized model allowed an effective and accurate assessment of the environmental impact of the thermal effluent because tidal and tidal residual currents play an important role in the advection and diffusion of thermal effluent.