SlideServe
Télécharger Obtenir Pro
Menu
Accueil Pro
Préférences
ApparenceLight Aide et commentaires
© SlideServe · v2026

Diagnostic Ozone Sensitivity Tests: Insights from the St. Louis 8-Hour Ozone and PM2.5 Study

hayley avatar
hayley
12 diapositives · 261 Views · Aug 23, 2014

This report presents the findings of the St. Louis 8-Hour Ozone and PM2.5 Study, focusing on sensitivity tests conducted to evaluate ozone performance using the CAMx and CMAQ models. The analysis identified underestimation bias in modeled ozone levels, with CAMx demonstrating better performance than CMAQ. Key factors influencing ozone formation were explored, including sunlight intensity, vertical mixing, and volatile organic compounds (VOCs) in the St. Louis area. The report highlights recommendations for improving model accuracy and understanding urban ozone dynamics.

#diagnostic ozone sensitivity tests: insights from the st. louis 8-hour ozone and pm2.5 study #diagnostic ozone sensitivity tests: insights from the st. louis 8-hour ozone and pm2.5 study ppt #powerpoint #presentation
Diagnostic Ozone Sensitivity Tests: Insights from the St. Louis 8-Hour Ozone and PM2.5 Study - slide 1
01 / 12Diagnostic Ozone Sensitivity Tests: Insights from the St. Louis 8-Hour Ozone and PM2.5 Study
1 / 17

Télécharger la présentation

Diagnostic Ozone Sensitivity Tests: Insights from the St. Louis 8-Hour Ozone and PM2.5 Study
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation

Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement. Téléchargez la présentation en cliquant sur ce lien. Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.

F I N

Plus de contenu associé

Transcription de la présentation

  1. Diagnostic Ozone Sensitivity Tests the St. Louis 8-Hour Ozone and PM2.5 Study Ralph Morris, Ou Nogmoncol, Abby Hoats, Gerry Mansell and Chris Emery ENVIRON International Corporation St. Louis 8-Hour Ozone/PM2.5 Workgroup Meeting March 20, 2006

  2. Background • Phase I of the St. Louis 8-Hour Ozone and PM2.5 Study developed three 8-hour ozone episodes for the CAMx and CMAQ models • Working with the Four Modeling Hubs, the episodes were evaluated • Ozone performance characterized by a general underestimation bias • CAMx was performing better than CMAQ • Given time constraints, Modeling Hubs decided to focus on the CAMx model for 8-hour ozone

  3. Background • Ozone underestimation tendency • St. Louis urban core ozone hole overstated • Modeled ozone formation too slow so that peaks occur further downwind than observed • Magnitudes of the peaks comparable to observed • Potential causes of ozone performance • Insufficient sunlight intensity • Insufficient vertical mixing • Too little VOC in StL • Too much NOx in StL • Other???

  4. Sensitivity Tests • Analyze MM5 cloud estimates to see if excessive – attenuates photolysis rates • Perform sensitivity tests • Base 3 w/ Mech 3 (compare with Mech4) • Kz_min =1.0 m2/s • Kvpatch with Kz_min =2.0 m2/s • 1.5 x ISOP (biogenic) • 1.5 x non-ISOP VOC (anthropogenic) • 0.75 x NOx (anthropogenic)

  5. 8-hr Ozone June 21, 2002 CAMx Mech 4 Base 2

  6. 8-hr Ozone July 15, 2002 CAMx Mech 4 Base 2

  7. Example Cloud EvaluationFairly Good Agreement – No Over-statement MM5 Predicted Satellite

  8. June/July Episode Sensitivity • Mech 3: Norm Bias = -13% to -38% • Mech 4: Norm Bias = -9% to -32% • Mech 4 improves Bias by 2-5 percentage points • Likely due to renoxification reaction • Kzmin = 2.0 m2/s • Improves bias by ~2 percentage points

  9. June/July Episode Sensitivity • Mech 3 & Kzmin=2: Norm Bias –12% to –36% • 1.5 x Biogenic Isoprene Emissions • Improvement in June (south wind) episode with Norm Bias increasing 3-5 percentage points • Little effect for July episode • 0.75 x Anthropogenic NOx Emissions • Little effects (Norm Bias <+2% change) • Urban ozone increases offset by rural ozone reductions • 1.5 x Anthropogenic VOC Emissions • Minor (1 percentage point increase) improvements

  10. Base 3 Mech 3 Kz_min=2.0 1.5 x ISOP 0.75 x NOx June 21, 2002 Daily Maximum 8-Hour Ozone (ppb)

  11. Kz_min=2.0 Base 3 Mech 3 0.75 x NOx 1,5 x ISOP July 15, 2002 Daily Maximum 8-Hour Ozone (ppb)

  12. Emission Sensitivity Tests • 1.5xISOP emissions sensitivity buys about 5% points in bias for June 21, little effect on July 15 • June 21 has transport from south where high biogenic isoprene occurs • Supports rerunning biogenic emissions with MM5 temperatures adjusted to correct bias • 0.75xNOx & 1.5xnon-ISOP VOC less of an effect • Although overstated low-level NOx in urban core could still be part of the problem