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RESULTS FROM THE NORTH AMERICAN MERCURY MODEL INTER-COMPARISON STUDY (NAMMIS)
Citation:
BULLOCK, R., K. LOHMAN, C. SEIGNEUR, K. VIJAYARAGHAVAN, A. DASTOOR, D. DAVIGNON, N. E. SELIN, D. J. JACOB, T. MYERS, K. CIVEROLO, C. HOGREFE, J. KU, G. SISTLA, D. ATKINSON, AND T. BRAVERMAN. RESULTS FROM THE NORTH AMERICAN MERCURY MODEL INTER-COMPARISON STUDY (NAMMIS). Presented at 8th International Conference on Mercury, Madison, WI, August 06 - 11, 2006.
Impact/Purpose:
The objectives of this task are to continue development and improvement of EPA's mesoscale (regional through urban scale) air quality modeling systems, such as the Community Multiscale Air Quality (CMAQ) model, as air quality management and NAAQS implementation tools. This task focuses on needed research and development of air quality models targeted for a major CMAQ model release in FY08. Model development for a broad scope of application is envisioned. For example, CMAQ will need to be able to simulate air quality feedbacks to meteorology and climate as well as intercontinental transport. The 2008 release of CMAQ is timed to coincide with EPA/OAR's and the states' needs for an improved model for assessments of progress (mid-course corrections) in the post-SIP submittal timeframe.
Description:
A North American Mercury Model Intercomparison Study (NAMMIS) has been conducted to build upon the findings from previous mercury model intercomparison in Europe. In the absence of mercury measurement networks sufficient for model evaluation, model developers continue to rely on model intercomparison studies to gauge the level of modeling uncertainty and to identify the most important knowledge gaps leading to this uncertainty. Three regional-scale atmospheric mercury models have been applied for the NAMMIS: a mercury-specific version of the Community Multi-scale Air Quality (CMAQ) model, the Regional Modeling System for Aerosols and Deposition (REMSAD), and the Trace Element Analysis Model (TEAM). The modeling domain used by all of the regional-scale models covers the 48 contiguous United States, southern Canada, and northern Mexico. Three different global-scale atmospheric mercury models were applied to define three sets of initial condition and boundary condition (IC/BC) data for the regional study area. The global models applied were: the Chemical Tracer Model (CTM), the Global - Regional Atmospheric Heavy Metal (GRAHM) model, and the GEOS-Chem model. The regional-scale models have each used these three IC/BC sets along with identical meteorological and pollutant emissions input data to simulate atmospheric mercury transport, transformation and deposition. Through this highly structured model application process, the individual effects of IC/BC input data and science process treatments in the regional models are measured.