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Meteorology Modeling for Air Quality
Research Programs
Currently, the Fifth-Generation Pennsylvania State University (PSU)/National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) is the primary tool for providing meteorological fields for CMAQ. MM5 is widely used to generate meteorological characterizations of the atmosphere throughout the air-quality modeling community. For CMAQ, MM5 is applied to case studies (episodic, seasonal, and annual) at a variety of spatial scales using a series of one-way nested domains. MM5 is run retrospectively using four-dimensional data assimilation (FDDA) for a dynamic analysis of the simulation period. The output represents a dynamically-consistent multiscale meteorology simulation for various horizontal grid spacings ranging from continental to urban scales. The MM5 output is ultimately used in the Sparse Matrix Operator Kernel Emission (SMOKE)©1 (emissions) and CMAQ (chemistry) modules to describe the atmospheric state variables and the planetary boundary layer characteristics.
Model Development
We are also adding capability to the CMAQ system to use the Weather Research and Forecast (WRF) model for meterological simulation. WRF is the next-generation meteorology model which is intended to ultimately replace MM5, and it includes many of the features that are currently in MM5. It is also attractive for air-quality modeling applications because, unlike MM5, it contains mass-conserving equations. Collaborative work has begun toward implementing a nudging-based four-dimensional data assimilation capability in WRF, as well as developing a version of the Pleim-Xiu land-surface model (PX LSM) for WRF.
The Meteorology-Chemistry Interface Processor (MCIP) creates the off-line linkage between meteorological models and CMAQ for research and regulatory applications. MCIP is compatible with upgrades to the meteorological models that are used by CMAQ to preserve numerical and physical consistency between the meteorology and chemistry models. The details of code changes in the latest release (MCIPv2.3) can be found in Otte (2004).
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1Copyright 1999 MCNC—North Carolina Supercomputing Center</p>
REFERENCES
Otte, T. L. What’s new in MCIP? Preprints, 3rd Annual Models-3 User’s Conference, 18-20 October, Chapel Hill, NC, Community Modeling and Analysis System, CD-ROM 7.2 (2004).