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CRGAQS: CAMx Sensitivity Results

CRGAQS: CAMx Sensitivity Results. Presentation to the Gorge Study Technical Team By ENVIRON International Corporation November 15, 2006. Today’s Presentation. Describe CAMx sensitivity simulations Model configurations Performance for PM and light scattering/extinction

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CRGAQS: CAMx Sensitivity Results

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  1. CRGAQS:CAMx Sensitivity Results Presentation to the Gorge Study Technical Team By ENVIRON International Corporation November 15, 2006

  2. Today’s Presentation • Describe CAMx sensitivity simulations • Model configurations • Performance for PM and light scattering/extinction • Show all August results first • Then November results • Next Steps

  3. Model Configuration • Episodes • August 10-22, 2004 • Meteorology from MM5 Run 6, 36/12-km grids • Flexi-nesting to the 4-km grid • November 4-18, 2004 • Meteorology from MM5 Run 3, all grids • Identified issues in Run 1 • Small temporal profile problem for fires • No on-road vehicle ammonia emissions in 4-km grid

  4. Model Configuration • Review – “Run 1” configuration • Maximize model speed • Mechanism 4 – CF (static 2-mode PM chemistry) • Bott advection solver • No PiG • OMP parallel processing on Linux quad-CPU • O’Brien Kv profile with 0.1 m2/s minimum • 10-day model spin-up period • 36-km grid only first 8 days • 36/12-km grid last 2 days

  5. Model Configuration • “Run 2” • Fix known emission issues • Find new fire emission problems • “Run 3” • Use CMAQ Kv profiles with 1.0 m2/s minimum • “Run 4” • Double NH3 inventory in 4/12-km grids • “Run 5” • Halve POA+PEC fire emissions (Aug only)

  6. Performance Evaluation

  7. August Performance Evaluation

  8. August Performance Evaluation

  9. August Performance Evaluation

  10. August Performance Evaluation

  11. Run 2 Statistics August NO3 August SO4

  12. Run 2 Statistics August NH4 August OC

  13. Run 2 Statistics August EC August Primary Fine

  14. Run 2 Statistics August Primary Coarse August Total PM2.5

  15. Run 2 Statistics August Total PM10 August Bscat

  16. Dry Light Scattering

  17. Predicted Organic Aerosol Components

  18. Run 2 Results • High SO4 and NO3 from incorrect fire emissions • Gorge not affected: performance OK for SO4 and NO3 • But NH3 is low • OC shows extremely high localized peaks from the fire emissions (POA) • OC over predictions in Gorge from biogenic SOA • Much less impacts from other SOA components • Under prediction of EC (especially at high observed values) • PM2.5 tended to be too high • PM10 was too low at IMPROVE sites • Why apparently too high at Gorge sites?

  19. Run 2 Results • 24-hr dry Bscat at Gorge sites tended to be too high • Hourly dry Bscat at Gorge monitors show over predicted spikes not observed by the nephelometers. • Individual PM concentrations at Mt. Zion show: • Spikes in the FINE & COARSE mass accounted for a majority of the Bscat • The spikes corresponded well with the spikes in Bscat • During the peak Bscat of 206 Mm-1 , ~150 was from this group • OC, whose maximum hourly concentration was 15 ug/m^3, contributed a maximum of 60 Mm-1 to Bscat

  20. Run 3 Results

  21. Run 3 Results • Secondary PM changed little compared to Run 2 • Primary PM and Bscat showed small reductions as the enhanced mixing diluted the concentrations • Gorge sites closest to Portland (Steigerwald, Mt. Zion, and Strunk Rd) had the largest reductions in Bscat • Hourly time series also show lower spikes in the Bscat in Run 3 compared to Run 2

  22. Run 4 Results

  23. Run 4 Results • Doubling NH3 emissions had no impact on SO4 • NO3 increases generally occurred in Puget Sound area • Smaller NO3 increases extend across eastern WA and OR • Daily Bscat changed less than 3 Mm-1 on all dates at the Gorge sites. • Hourly Bscat was not significantly different from Run 2

  24. Run 5 Results

  25. Run 5 Results • EC and OC were reduced the most in the Washington interior, and only slightly at the Gorge monitoring sites. • Gorge EC and OC were reduced most during northerly winds (August 13) • Monitors in the east showed the largest reduction • Hourly Bscat show similar patterns between Run 2 and Run 5 • Some slightly lower spikes, particularly at the eastern sites (like Towal Rd)

  26. November Performance Evaluation

  27. November Performance Evaluation

  28. November Performance Evaluation

  29. November Performance Evaluation

  30. Run 2 Statistics November NO3 November SO4

  31. Run 2 Statistics November NH4 November OC

  32. Run 2 Statistics November EC November Primary Fine

  33. Run 2 Statistics November Primary Coarse November Total PM2.5

  34. Run 2 Statistics November Total PM10 November Bext

  35. Dry Light Scattering(west Gorge)

  36. Dry Light Scattering (east Gorge)

  37. Run 2 Results • Nitrates were more abundant in November than in the August simulation • SO4 and OC were highest near urban centers (Portland and Seattle), and along I-5 • Near the Gorge, SO4 was highest on November 12 and 13 • SO4 at IMPROVE sites was well-predicted • SO4 at Gorge monitors tended to be underpredicted • NO3 performance was scattered • OC, fine, and coarse matter had a few over predicted extremes • PM2.5 at the FRM network was over predicted

  38. Run 2 Results • Hourly Bscat at western Gorge monitors is over predicted (large spikes) • Bscat and PM time series at Mt. Zion show: • Spikes in OC correspond to the Bscat spikes • The largest contribution to Bscat from OC = 4*[OC]max = 4*75 = 300, which accounts for only half of the total computed Bscat • Spikes in FINE and COARSE matter also match the Bscat spikes -- this adds up to 200 to Bscat at Mt. Zion • Hourly Bscat at eastern Gorge sites is under predicted (miss big haze event)

  39. Run 3 Results

  40. Run 3 Results • Enhanced mixing diluted concentrations of all species (esp. primary PM) • Changes were much greater than in the August Kv sensitivity test • Gorge sites closest to Portland showed the greatest reductions in Bscat spikes • Steigerwald Bscat dropped nearly 300 Mm-1 on November 6 compared to Run 2 (O’Brien Kv) • No siginficant change at eastern sites

  41. Run 4 Results

  42. Run 4 Results

  43. Run 4 Results • Nitrates were much higher with doubling of ammonia emissions • Western Gorge area showed the largest increases early in the episode (Nov 6-9) • Sulfate increases were more spatially confined • Bscat, PM2.5 and PM10 were slightly higher • Bscat changes at Gorge sites were higher at the western sites • However, changes were relatively insignificant

  44. Moving Forward • More sensitivity/diagnostic runs • Revise fire emissions • Reduce primary fine/coarse emissions in both episodes • Check role of biogenic emissions in OC over predictions • Identify observed components of high scattering at eastern Gorge sites

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