models-3 users’ workshop 2003 research triangle park, nc computational chemodynamics laboratory...

Models-3 Users’ Workshop 2003Research Triangle Park, NC

Computational Chemodynamics LaboratoryEOHSI - Exposure Measurement & Assessment Division

Evaluating Ozone Predictions from Photochemical Models Using NE-OPS 1999

ObservationsQing Sun, Anatharaman Chandrasekar, Panos G.

GeorgopoulosEnvironmental and Occupational Health Sciences Institute, a joint

project of UMDNJ — R. W. Johnson Medical School and Rutgers University

170 Frelinghuysen Road, Piscataway, New Jersey 08854

C. Russell PhilbrickPenn State University, Department of Electrical Engineering and

Applied Research Laboratory, University Park, Pennsylvania

Bruce DoddridgeUniversity of Maryland, Department of Meteorology, College Park,

Maryland

One Atmosphere, One Community, One Modeling System: Models-3 Users’ Workshop

October 27-29, 2003Research Triangle Park, North Carolina



Outline

• Summary of the NE-OPS 1999 study

• Applications of and evaluation of CMAQ and CAMx

• Discussions and future work



Summary of the NE-OPS Study

• North East - Oxidant and Particle Study (NE-OPS), sponsored by EPA

• Objectives:– Determine conditions leading to high O3 and PM– Local vs distant sources– Roles of meteorological properties

• Participants: Penn State, Millersville, Harvard SPH, Univ Maryland, SUNY at Albany, Rutgers, Brookhaven Nat Lab, PNNL, etc

• Location: centered at the Baxter water treatment plant in north Philadelphia

• Time span: 1999 – 2001 (this study uses data from July 11-25, 1999)

• Included both meteorological and air quality measurements• Measurements approaches: instrumented airplanes; Radar wind

profiler/RASS sounder; Lidar atmospheric profile sensor; tethered balloons; ozonesondes, rawinsondes, and ground based measurements of PM compositions.



Nested Modeling Domain



Monitor Stations and NE-OPS Flight Tracks



Problem specifications

• Modeling period: 7/11/1999 to 7/25/1999• Three levels of nested grids (36km, 12km and

4km)• Grid dimensions: 72×60, 69×54 and 63×72• 14 Layers for CMAQ, 8 for CAMx• Meteorology prepared with MM5• Emissions prepared from USEPA’s 1998 NET

inventory, using SMOKE



NOx and VOC Emissions



Model Configuration

CMAQ CAMx

Advection Bott scheme Smolarkiewicz scheme

Turbulence K-theory based eddy formulation

K-theory based eddy formulation

Chemistry RADM2 or CB4 CB4 mechanism with updated isoprene chemistry

Number of gas-phase chemical species

59 (RADM2); 36 (CB4)

25

Number of chemical reactions

157 (RADM2); 93 (CB4)

96



Run Time Comparison

CMAQ CAMx

Nesting 1-way nesting 2-way nesting

Type of machine used

Sun Fire 280R with dual 750 Hz UltraSPARC-III CPU and 4GB memory

Linux PC with single AMD Athlon XP 1800 and 1GB memory

Run Time 3-4 hours per model day for each grid

About 0.5 hour per model day for the 3-level nested grid



Daily maxima of ground level ozone for 7/18/1999

CMAQ

CAMx

AirNow




CMAQ

CAMx

AirNow



Space-time paired comparisons of ground level ozone with observation

CMAQ CAMx



Quantile-quantile comparisons of ground level ozone with observation

CMAQ CAMx



Model-to-model comparison



Ozone Time Series Comparison between Model Predictions and Observations at Middlesex, NJ



Ozone Time Series Comparison between Model Predictions and Observations at Philadelphia



Selected NEOPS Flights



Comparison with flight measurements (I)



Comparison with flight measurements (II)



Conclusions

• The two models, CMAQ and CAMx, predicted similar general patterns of pollutant spatial and temporal distributions

• There is considerable discrepancy of predictions by the two models for surface ozone:– CAMx significantly over-predicting ozone peaks

for certain days during the high ozone hours– CAMx predicts close-to-zero ozone during the

nights, probably reflecting the failure of the model to sufficiently account for the effects of an upper layer ozone reservoir accumulated during the daytime hours for the high ozone days



On-going and future work

• Parallel processing on Linux cluster• Emissions from 1999 and projected 2001(?)

NEI• Seasonal or annual runs of CMAQ and CAMx • Linking the annual air quality applications with

MENTOR/SHEDS for exposure/dose analyses

MENTOR – Modeling Environment for Total Risk

SHEDS – Stochastic Human Exposure and Dose Simulation



Acknowledgements

• State of New Jersey Department of Environmental Protection (NJDEP) funded Ozone Research Center (ORC)

• U.S. EPA Center for Exposure and Risk Modeling (CERM) (EPAR-827033)

• U.S. EPA funded NorthEast Oxidant and Particle Study (NE-OPS) (EPA-TPSU-UMDNJ-826373-14)

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