||MCNC, Research Triangle Park, NC. Information Technologies Div. ;National Oceanic and Atmospheric Administration, Research Triangle Park, NC. Air Resources Lab.;Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Research and Exposure Assessment Lab.
A variety of non-emissions-related sensitivity and shock tests are performed on the Regional Oxidant Model (ROM) version 2.2, a regional-scale, three-layer, Eulerian-grid air quality model. Variables perturbed include the initial conditions, boundary conditions, cloud transmissivities, horizontal diffusivities, layer heights, temperature, deposition velocity, and vertical fluxes. The sensitivity tests fall into three groups: (1) boundary-conditions-related tests, (2) layer-related tests, and (3) miscellaneous meteorological tests. The authors find that the ROM2.2 is particularly sensitive to perturbations in the height of layer 2 and in cloud transmissivity. Perturbations in deposition velocity, upper boundary conditions, layer 1 heights, temperature, and vertical fluxes can also produce significant changes in model predictions. Lateral boundary conditions and initial conditions play relatively minor roles in the model predictions for more polluted areas.