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O UTLINE Why are we interested in linking GEOS-CHEM with regional air quality model (CMAQ)?

O UTLINE Why are we interested in linking GEOS-CHEM with regional air quality model (CMAQ)? Technical issues to consider when linking GEOS-CHEM & CMAQ Upcoming results from two relevant EPA projects. Why does EPA want to link GEOS-CHEM with regional air quality model (CMAQ)?.

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O UTLINE Why are we interested in linking GEOS-CHEM with regional air quality model (CMAQ)?

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  1. OUTLINE • Why are we interested in linking GEOS-CHEM with regional air quality model (CMAQ)? • Technical issues to consider when linking GEOS-CHEM & CMAQ • Upcoming results from two relevant EPA projects

  2. Why does EPA want to link GEOS-CHEM with regional air quality model (CMAQ)? • Intercontinental transport of pollutants • What are the impacts of trans-Pacific transport of O3, PM, and other pollutants on U.S. air quality? • How about trans-Atlantic transport (export)? • Climate and Air Quality studies • Climate change impacts on air quality • Air quality impacts on climate • Continental domain CMAQ simulations • Can model results improve using the boundary conditions provided by the GEOS-CHEM?

  3. U.S. CMAQ Modeling: O3(e.g., 1996 July Max in ppb) 56 99 149 62 134 76 132 139 137 107 126 119 131 215 127 144 113 194

  4. USEPA Community Multiscale Air Quality Model (CMAQ) • Gas phase chemical mechanisms: SAPRC99, CB4, RADM2 • Aerosols: Binkowski and Roselle [JGR, 2003] • Resolution ranges from regional (e.g., 36 km2 grid) to urban (e.g., 4 km2 grid) scale • Vertical layers range (e.g., 15 to 23) and go up to 100mb • Emission fields based on USEPA National Emissions Inventory (e.g., NEI99 v2), BEIS 3.10, and Mobile 6 • Meteorology typically generated using the NCAR/Penn State Mesoscale Model (MM5 v3)

  5. Spatial Resolution Issues • Scale of CMAQ simulations • regional (e.g., 36×36 km2) scale • nested finer scale (e.g., 12×12 km2, 4×4 km2) • Hourly time scale for input and output • Matching GEOS-CHEM fields with CMAQ for boundary conditions • If 4×5, > 10 CMAQ grids to 1 GEOS-CHEM grid along vertical boundaries • Different projections (cartesian vs conformal)

  6. CMAQ upper boundary conditions • CMAQ typically up to 100 mb • With fairly coarse layers at top, tropopause not resolved • Without tropopause dynamics, lower stratospheric [O3 ] not an option • O3 fluxes from GEOS-CHEM would be an option

  7. Consistencies between GEOS-CHEM and CMAQ • Emission inventories over U.S. • Global Climate Modeling for future climate change scenarios • MM5 mesoscale model can use GCM BCs • Similar greenhouse gas scenarios • Chemical fields simulations • O3 • Speciated aerosols (sulfate, nitrate, organics,…) • Hg

  8. Upcoming results from 2 relevant EPA studies • Climate Impacts on Regional Air Quality (CIRAQ): USEPA ORD • Intercontinental transport and Climate Effects of Air Pollution (ICAP): USEPA OAQPS

  9. Simulations from CIRAQ Project(Climate Impacts on Regional Air Quality) For U.S. Continental Domain • 10-yr MM5 mesoscale model runs (complete 2004) • 1990-2003 • 2040-2050 • 36×36 km2 resolution • GISS II’ GCM boundary conditions (collaboration with Harvard) • IPCC A1B greenhouse gas emission scenario • 5-yr CMAQ simulations (complete 2006) • 1999-2003 • 2045-2050 • O3 and PM predictions • 36×36 km2 resolution • Base NEI99 v2 emissions for 1st incremental phase tests • SAPRC chemical mechanism • Boundary conditions driven by GEOS-CHEM (with GISS II’ GCM, IPCC A1B) (collaboration with CMU and Harvard, through STAR EPA coops) • Analysis of results included in EPA GCRP air quality national assessment report in 2007

  10. Simulations from CIRAQ Project(Climate Impacts on Regional Air Quality) • Future (2050) air quality emission scenarios • Technology assessments for mobile and utility sectors • Population and economic projections consistent with IPCC, more spatially resolved • External collaborations to be determined • Proposals under review at STAR program • CMAQ 2050 simulations with future air quality emission scenarios (tentatively planned for 2010 EPA GCRP AQ assessment)

  11. Results from ICAP Project(Intercontinental transport and Climate Effects of Air Pollution) • 2001 trans-Pacific and trans-Atlantic domain CMAQ simulations, 108-km grid (spring 2004) • 2001 national domain CMAQ simulations, 36-km grid; episodic eastern & western US domains, 12-km grid (spring/summer 2004) • Emission inventory for Asia (O3, PM, Hg)

  12. ICAP Trans-Pacific Domain ICAP Trans-Atlantic Domain

  13. ICAP: Refinement of Asian emission inventory for CMAQ Trans-Pacific Simulations NO emissions

  14. Air Quality Modeling over China : PM 2.5

  15. Next Directions at EPA • Assessment of future climate change impacts on AQ expanded to 2100 • Develop bidirectional feedback between CMAQ and MM5/WRF for aerosol impacts on meteorology • Agency long-term planning for intercontinental transport research underway

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