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An Adaptive Grid Version of CMAQ for Improving the Resolution of Plumes

An Adaptive Grid Version of CMAQ for Improving the Resolution of Plumes. Fernando Garcia-Menendez Yongtao Hu M. Talat Odman 8 th Annual CMAS Conference 20 October, 2008. Background. Adaptive Grid Algorithm (1997-2001)

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An Adaptive Grid Version of CMAQ for Improving the Resolution of Plumes

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  1. An Adaptive Grid Version of CMAQ forImproving the Resolution of Plumes Fernando Garcia-Menendez Yongtao Hu M. Talat Odman 8th Annual CMAS Conference 20 October, 2008 Georgia Institute of Technology

  2. Background • Adaptive Grid Algorithm (1997-2001) • Srivastava, R. K., D. S. McRae, and M. T. Odman (2000) : An adaptive grid algorithm for air quality modeling, J. Comput. Phys., 165, 437-472. • Adaptive Grid Air Quality Model (2001-2004) • Variable Time Step Algorithm (2004-2007) • and now … Georgia Institute of Technology

  3. Adaptive Grid CMAQ • AG-CMAQ is a sophisticated piece of code that was built on top of CMAQ Version 4.5 by remaining faithful to the “Models-3” concept • It has been verified • It can be applied through the existing framework • No additional input files are necessary • To use AG-CMAQ in your applications, adjust the driving force of grid adaptations by either: • Supplying a separate emissions input file for sources to be resolved • Or changing the adaptation weight function to focus on different pollutants, terrain, or other features. • We can show you how! dependently independently Georgia Institute of Technology

  4. Code Verification • Expectation: When AG-CMAQ is not adapting it should produce the same results as the standard CMAQ • Outcome: The results are practically the same with very small and random differences, except for biogenic organic and nitrate aerosols where the differences are still small ( < 0.1 mg m-3) but have a pattern. The source is coming from the aerosol module. Difference in Biogenic SOA Difference in Nitrate Georgia Institute of Technology

  5. Rx Burn at Ft. Benning: PM2.5 CMAQ 1.33 km grid AG-CMAQ ~ 100 m grid Georgia Institute of Technology

  6. CMAQ Bug Alert! • Several deeply hidden bugs were found in CMAQ • Instability in advection due to improper time step • CFL stability condition is violated if the max. wind speed decreases by more than 1/3 during the output time step • Incomplete advection due to time step not dividing MINSYNC wholly. • Incomplete horizontal diffusion due to misplaced update of concentration array • Smagorinsky formulation in HDIFF assumes Cartesian coordinates (watch out Hemispheric Applications!) • Details and fixes are in my website • http://people.ce.gatech.edu/~todman/ Georgia Institute of Technology

  7. Problem with WRF! UWIND is oscillating 1.3 km grid resolution Georgia Institute of Technology

  8. Atlanta Smoke Event (CMAQ)

  9. Atlanta Smoke Event (AG-CMAQ)

  10. Atlanta Smoke Event (28 Feb. 2007) Z Z Z Z Georgia Institute of Technology

  11. Emissions Chemical Coupling Handover d = downwind distance MM5 (WRF) Adaptor CMAQ Smoke Impact Simulation System Daysmoke Ambient concentrations Parcel/Puff/Plume concentrations Parcels Parcels mixed in grid cells Meteorology Grid Support? Distributions Grid Grid Grid Concentrations Meteorology Meteorology Particles/CCN Georgia Institute of Technology

  12. Daysmoke

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  34. Poster • A sub-grid scale model for the treatment of biomass burning plumes in CMAQ by Aika Yano et al.

  35. Acknowledgements • Strategic Environmental Research and Development Program (SERDP) • Joint Fire Science Program (JFSP) • U.S. Forest Service • Dr. Gary L. Achtemeier Georgia Institute of Technology

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