1 using hemispheric-cmaq to provide initial and boundary conditions for regional modeling joshua s....
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Using Hemispheric-CMAQ to Provide Initial and Boundary Conditions for Regional
Modeling
Joshua S. Fu1, Xinyi Dong1, Kan Huang1, and Carey Jang2
1University of Tennessee, Knoxville
2Office of Air Quality Planning and Standards, USEPA
Oct 17, 2012
1111thth Annual CMAS Conference Annual CMAS Conference
15-1715-17th th October, 2012October, 2012
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Objective
Study the potential applications of Hemispheric-scale CMAQ (H-CMAQ) to:
Provide initial and boundary conditions (IC/BC) for Provide initial and boundary conditions (IC/BC) for regional modelingregional modeling
Provide support for hemispheric scale studies with Provide support for hemispheric scale studies with CMAQCMAQ
intercontinental transportintercontinental transport public relevant background ozonepublic relevant background ozone Arctic black carbonArctic black carbon
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Motivation Uncertainties remain in current methods to
produce IC/BC
Profile IC/BC: Limited horizontal and vertical variationsProfile IC/BC: Limited horizontal and vertical variations Ordinary downscaling IC/BC: excessive transport of OOrdinary downscaling IC/BC: excessive transport of O33 in the upper in the upper
tropospheretroposphere Dynamic downscaling: inconsistent modeling system, discontinuity Dynamic downscaling: inconsistent modeling system, discontinuity
between different chemical and transport schemesbetween different chemical and transport schemes
Uncertainties remain in current global-regional modeling application Introduce uncertainties during downscalingIntroduce uncertainties during downscaling Global and regional models are not using exactly the same Global and regional models are not using exactly the same
emissions over the same domainemissions over the same domain
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Methodology OverviewHow to evaluate the capability of H-CMAQ to reproduce air pollutants concentrations, and provide IC/BC for regional CMAQ modeling ?
GEOS-Chem
Re-projection
Species mapping
Re-projection
Layer interpolation
Dynamic downscaling
H-CMAQ
Nest down
IC/BC IC/BC
Regional CMAQ Regional CMAQ
Part 1. Compare modeling results from two different models
Part 3. Compare modeling results from two different CMAQ simulations driven by two different sets of IC/BCs
Part 2. Produce IC/BC
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Domain ConfigurationGEOS-Chem H-CMAQ
CMAQ GEOS-Chem H-CMAQ CMAQ
Model Version V9-01-02 V4.7.1 V4.7.1
Horizontal Grid Spacing
2 x 2.5° 108 x 108 km 36 x 36 km
Vertical Grid Spacing
48 layers (0.01mb top)
34 layers (100mb top)
34 layers (100mb top)
Projection Geographic Lat/Lon Polar Lambert Conformal Conic
Met Field GEOS-5 WRFv3.2.1 WRFv3.2.1
3 Domains:- Global:- Global:
GEOS-ChemGEOS-Chem- North Hemisphere: - North Hemisphere:
H-CMAQH-CMAQ- CONUS:- CONUS:
CMAQCMAQ
Model Configurations
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H-CMAQ Emission Preparation Base data: 2008 Annual Emission Database for Glob
al Atmospheric Research (EDGARv4.2) Species: SO2, NOx, CO, NMVOC, NH3, PM10, PM2.5, OC, BC Resolution: 16 sectors, annual emission, 0.1x0.1°grid spaci
ng Three processing steps:
Temporal Allocation Speciation Vertical Distribution
0
100
200
300
400
500
600
700
800
900
1000
0 5 10 15 20
Percentage (%)
Hei
ght (
met
ers)
Power Generation
Hourly Scaling Factors
Vertical Profile
0
0.5
1
1.5
2
2.5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Hour
Scal
ing
Fact
or
Industry
Power Generation
Residential
Transportation
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Model-ready Emissions
SO2 (10-10 moles/(m2s))
EDGAR
H-CMAQ
H-CMAQ emission in July 2008 compared with EDGAR emission, with both units transferred to moles/(m2s)
NOx (10-10 moles/(m2s)) CO (10-7 moles/(m2s))
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H-CMAQ Meteorology Field
Parameters Russia US China Benchmark*
T2 Bias (K) -0.51 -0.64 -1.35 ±0.5Gross Error(K) 1.95 2.27 2.55 ≤2IOA 0.95 0.94 0.92 ≥0.8
Wind Speed Bias (m/s) 0.26 -0.33 0.23 ±0.5RMSE (m/s) 1.57 1.83 1.66 ≤2
IOA 0.77 0.72 0.72 ≥0.6Wind Direction
Bias (deg) 0.99 0.05 2.6 ±10Gross Error (deg) 37.01 36.84 48.82 ≤30
Water VaporMixing Ratio
Bias (g/kg) -0.25 0.71 -0.36 ±1Gross Error (g/kg) 1.16 1.62 1.91 ≤2IOA 0.91 0.93 0.94 ≥0.6
Observation Sites WRF Evaluation Statistics (July, 2008)
WRF performance is evaluated against NCDC data Three countries (Russia, United States, and China) are selected to Three countries (Russia, United States, and China) are selected to
show the hemispheric scale WRF performanceshow the hemispheric scale WRF performance Higher latitude region has a generally better predictions from WRF, Higher latitude region has a generally better predictions from WRF,
while the overall meteorology filed is reliable for H-CMAQwhile the overall meteorology filed is reliable for H-CMAQ
*Bench mark values suggested by Emory et al. (2001)
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Global Scale Models Performance in CONUS
GEOS-Chem -Projection distortion along the latitude -Hard to capture peak values
H-CMAQ-Projection distortionalong the diagonal
StatisticsDaily Max O3 July 2008
Both GEOS-Chem and H-CMAQ generally reproduce ozone distribution over CONUS
ppbv
ppbv
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Boundary Conditions Profile BC derived from H-CMAQ is close to dynamic downscaled BC fr
om GEOS-Chem
East Boundary
0
2
4
6
8
10
0 20 40 60 80 100
ozone concentration (ppbv)
Hei
ght (
km)
North Boundary
0
2
4
6
8
10
0 20 40 60 80 100
ozone concentration (ppbv)
Hei
ght (
km)
West Boundary
0
2
4
6
8
10
0 20 40 60 80 100
ozone concentration (ppbv)
Hei
ght (
km)
South Boundary
02468
10
0 20 40 60 80 100
ozone concentration (ppbv)
Hei
ght (
km)
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Modeling with Different IC/BCs
Driven by IC/BC from GEOS-Chem
Driven by IC/BC from H-CMAQ
StatisticsDaily Max O3 July.2008
ppbv
ppbv
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Summary Preliminary Conclusions:
Hemispheric-CMAQ is capable of reproducing the air quality generally aHemispheric-CMAQ is capable of reproducing the air quality generally agree well with observation over CONUS domain, and IC/BC derived from gree well with observation over CONUS domain, and IC/BC derived from Hemispheric-CMAQ is close to that from GEOS-ChemHemispheric-CMAQ is close to that from GEOS-Chem
Regional CMAQ simulation over CONUS domain demonstrate the capabiRegional CMAQ simulation over CONUS domain demonstrate the capability of H-CMAQ to provide IC/BC for regional modelinglity of H-CMAQ to provide IC/BC for regional modeling
Next steps:
Stability check: H-CMAQ derived IC/BC performance in different seasons,Stability check: H-CMAQ derived IC/BC performance in different seasons, at different regional areas at different regional areas
Inter-continental transport application: can H-CMAQ better track the polInter-continental transport application: can H-CMAQ better track the pollutants transportation ?lutants transportation ?
Update H-CMAQ emission with local emission inventory: NEI, EMEP, BRAUpdate H-CMAQ emission with local emission inventory: NEI, EMEP, BRAVO, CAC, INTEX-B …VO, CAC, INTEX-B …
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Acknowledgement
The authors acknowledge GEOS-Chem team for their The authors acknowledge GEOS-Chem team for their user support.user support.
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Thanks !