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MM5/CAMx Model Diagnostic andMM5/CAMx Model Diagnostic andSensitivity Analysis Results:Sensitivity Analysis Results:Recent Diagnostics and PARecent Diagnostics and PA

Central California Ozone Study: Bi-Weekly Presentation 4

T. W. TescheDennis McNallyHarvey Jeffries

23 December 2003

OThree Chemistry Recent Analyses & ResultsRecent Analyses & Results

Recent Reporting Diagnostic Experiments—Round 2 (sent 15 Dec ’03) Diagnostic Experiments—Round 3 (sent 18 Dec ’03) Process Analysis Spreadsheets– (sent 22 Dec ’03) Bi-Weekly Presentation Materials– (sent 22 Dec ’03)

Round 2 Diagnostic Analyses Run Bnp3v3 (NOx emissions decreased, VOC’s increased by factor of 3) Run B No Dry Deposition (dry deposition zeroed-out)

Round 3 Diagnostic Analyses Application of Kv Patch = 1.0 m2/s (CMAQ default value) Application of Kv Patch = 0.1 m2/s (CAMx default value) Re-run of Base B with new CAMx (ver 4.03) Re-run of VOC emissions scale-up run (Bn3) with new CAMx (ver 4.03)

Process Analysis Update (by Prof. Jeffries) Overview of Method as Applied to SJV’ Recent Results and Implications

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Findings of Round 2 Diagnostic Findings of Round 2 Diagnostic RunsRuns

Runs are diagnostic only; not intended to imply California inventories possess factor of 3 systematic errors across all categories.

Scalar increases (by factor of 3) in anthropogenic VOC and/or NOx inventories yield much greater ozone changes compared with MM5 sensitivity experiments.

Factor of 3 increase in NOx emissions substantially degrades model performance in the SJV and across the 4 km domain.

Factor of 3 increase in VOC emissions improves model performance statistically and graphically in the SJV; improvements across the 4 km domain are less.

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Round 2 Findings (concluded)Round 2 Findings (concluded) Factor of 3 VOC & NOx increases do not yield significant model

performance improvement Factor of 3 increase in VOC and decrease in NOx systematically

degrades model performance Removal of dry deposition process systematically degrades model

performance So far, VOC x3 scale-up run (Bv3) appears to shed most light on

potential causes of ozone underprediction bias in Sept ’00 episode; Round 2 results invite Process Analysis focus on role of VOC emissions

in producing ozone in the SJV.

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Findings of Round 3 Diagnostic Findings of Round 3 Diagnostic RunsRuns

Application of Kv_Patch (minimum of 1.0 m2/s) yields: Slight improvement (~ 0.4 ppb) in the accuracy of peak 1-hr ozone predictions

over all monitoring stations in the SJV subdomain Slight degradation in episode average mean normalized bias (increases by ~ 1.3

ppb) Slight degradation in episode average mean normalized gross error (increases by

~0.7 ppb) Slight degradation in model’s underprediction tendency (non-normalized bias

increases from –18.6 ppb to –19.3 ppb, averaged across all SJV monitors for the 16-20 Sept ’00 episode

Overall, no major change in model’s gross statistical response, except slight worsening of the existing ozone underprediction problem.

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Round 3 Findings (concluded) Round 3 Findings (concluded) Migration to the newest version of CAMx (ver 4.03) appears to have:

No significant impact on the model’s response to significant precursor emissions changes.

Slight impact on model response when tested with emissions change scenario (Base Bv3: VOC’s scaled up by factor of 3), suggesting that this response would hold for other types of emissions changes as well.

Overall, no major impact on CAMx sensitivity to precursor emissions changes in migrating to newer version of model.

OThree Chemistry Update on Process Update on Process Analysis Analysis

Methodology Use of CAMx (ver 4.03) Base B Simulation Integrated Process Rate (IPR) Process Analysis Tools from UT/UNC Package installed in

CAMx (ver 4.03)

Analysis Sub-Areas Elk Grove, Parlier (downwind Fresno), Arvin (downwind Bakersfield)

Initial Results Refer to PDF Files Transmitted 23 Dec ’03 before today’s call Currently unexplained vertical mixing processes (related to PBL heights and diffusivities)

appear to affect chemical processing, day and night. Potential for systematic overestimation of low reactivity VOC emissions (PAR) in CCOS

inventory compared with other cities in U.S? Insufficient supply of radical species in model to promote significant ozone formation?

OThree Chemistry Process Analysis Focus Sub-Process Analysis Focus Sub-AreasAreas

Elk Grove

Arvin

Parlier

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Vertical Ozone Slice Plots At ArvinVertical Ozone Slice Plots At ArvinEast-West Slice on 18 Sept ’00 at 1500 PST

Base B

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Example of Unusual Vertical Mixing Example of Unusual Vertical Mixing Phenomena Phenomena

North-South Slice on 18 Sept ’00 at 1500 PST

Base B

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VOCs (Kmoles) in CCOS Domain on 29 VOCs (Kmoles) in CCOS Domain on 29 Jul ’00Jul ’00 BAAQMD staff identified potential concerns w/ BAAQMD staff identified potential concerns w/ inventory speciationinventory speciation

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VOCs (kmoles) in CCOS Domain on 29 VOCs (kmoles) in CCOS Domain on 29 Jul ’00 Jul ’00 BAAQMD inventory speciation QA performed in BAAQMD inventory speciation QA performed in late Aug ‘03late Aug ‘03

OThree Chemistry Anthro VOC Emissions At Arvin:Anthro VOC Emissions At Arvin: Unexpectedly high fraction of low reactive emissions (PAR) in Unexpectedly high fraction of low reactive emissions (PAR) in

inventoryinventory Aggregate VOC Emissions Composition

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OThree Chemistry Anthro VOC Emissions In Anthro VOC Emissions In HoustonHouston

Typically smaller fraction of low reactive emissions (PAR) in HGA Typically smaller fraction of low reactive emissions (PAR) in HGA

inventoryinventory Aggregate VOC Emissions Composition

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Next StepsNext Steps

Emerging Need for Coordinated Review of VOC speciation methods in current CCOS modeling inventory By ARB, Alpine Geophysics inventory staffs.

MM5 Sensitivity Simulation(s) Implementation of FDDA findings from NOAA and Bay Area Modeling Results; Adaptation of NOAA Land Use and Related Parameter Specifications

CAMx Sensitivity Simulations Across-the-Board Adjustment of VOC emissions speciation Local metropolitan (Fresno, Bakersfield) VOC emissions sensitivity experiments

(mass emissions rates, speciation assumptions) Sensitivity to ICs/BCs/TCs (GEOS-CHEM boundary conditions) Sensitivity to diurnal/spatial PBL height and diffusivity profile estimates

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Next Steps (continued)Next Steps (continued)

Consider Merits of Invoking Other Probing Tools and Corroborative Models OSAT, DDM MAPPER