Improved High-Fidelity Forecasting Capability using Combined Mesoscale and Microscale Models

We propose to evaluate the improvement of atmospheric transport and dispersion model accuracy by synergistically combining mesoscale (NWP) and microscale (CFD) models in a manner suitable for an operational environment. The feasibility of a fully-coupled, combined, operational model will be addressed in the Phase I study by evaluating improved urban area transport behavior using OMEGA generated wind and turbulence data as boundary condition data to the CFD-Urban transport and dispersion model for simulations corresponding to the Urban 2000 Field Test. The NWP and CFD models will be fully-coupled in a two-way mode in Phase II, by supplying microscale model generated urban and surface layer parameterization data to the mesoscale model, and mesoscale model generated wind and turbulence field data to the microscale model. During Phase I, microscale, volumetrically generated urban area parameterizations will be directly compared to the urban canopy parameterizations used in the mesoscale model, and the computational framework to couple both models operationally will be assessed. Phase II will develop an operationally suitable computational framework to fully couple these and other NWP and transport and dispersion models, and will provide more accurate and timely wind field data for use in atmospheric transport and dispersion models.