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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 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 • Show all August results first • Then November results • Next Steps
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
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
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)
Run 2 Statistics August NO3 August SO4
Run 2 Statistics August NH4 August OC
Run 2 Statistics August EC August Primary Fine
Run 2 Statistics August Primary Coarse August Total PM2.5
Run 2 Statistics August Total PM10 August Bscat
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?
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
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
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
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)
Run 2 Statistics November NO3 November SO4
Run 2 Statistics November NH4 November OC
Run 2 Statistics November EC November Primary Fine
Run 2 Statistics November Primary Coarse November Total PM2.5
Run 2 Statistics November Total PM10 November Bext
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
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)
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
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
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
