Adaptation of analytic diffusivity formulations to Eulerian grid model layers of finite thickness

A Kalman Filter based sensitivity study of the influence of boundary layer parameters (e.g., vertical turbulent exchange coefficient and the mixing layer height) and emission data was conducted on the predicted-observed concentration errors of the REM-CALGRID (RCG) model. To accomplish this, operational ground-based O3 and NO2 were assimilated into the RCG model during a simulation covering summer and winter conditions. Analysis of the noise values indicated that a systematic error in the vertical exchange process was periodically impacting deposition fluxes and ground level concentrations. While the Kalman filtering analysis didn’t tell us, in detail, the correct way to proceed, it did identify the problematic module and the statistical-based findings were the starting point for revisiting the vertical flux formulation within the model.