2006-2008 GEOS-Chem Simulations for CMAQ Initial and Boundary Conditions

1Yun-Fat Lam, 1Joshua S. Fu, 2Daniel J. Jacob, 3Carey Jang and 3Pat Dolwick

1 University of Tennessee, Knoxville2 Harvard University

3 EPA-OAQPS

Oct 11, 2010

CMAS Conference

Outline of talk

1. Background and Motivation

– Long-range transport

– Increase in background concentration

2. Development & Methodology

– New CB05 with AE5 mapping table

3. Global and Regional Model Configurations

– GEOS-Chem and CMAQ simulation

4. Sensitivity to Initial & Boundary Conditions

5. Conclusions

Why boundary condition is important to U.S. air quality?

• Long-range transport of air pollutant 1

• Enhancement of background pollutants concentration 2

– The Canadian and Mexican pollution enhancement averages 3-4 ppb in the US in summer 3

– peaking at 33 ppb in upstate New York (on a day with 75 ppb total ozone) and 18 ppb in

1Heald, C.L., et al., J. Geophys. Res. (2003), Mian Chin, et al., Atmos. Chem. Phys. (2007)2Vingarzan R., Atmos. Envir. (2004), Ordonex C., et al., Geophys. Res. L. (2007)3 Huiqun Wang, et al., Atmos. Envir. (2009), 43, 1310–1319

Canadian and Mexican pollution enhancement

GEOS-Chem Simulations

• 2005–2008 GEOS-Chem simulations– To study the inter-annual variability of boundary

condition from each bound (North, East, South and West)

• Propose a fixed domain for sharing CMAQ initial and boundary conditions using 34-layer IC/BC file– Study the impacts of using 24L IC/BC Vs.

34Lto24L – Identify the effects of this technique to CMAQ

output.

Global Model Configuration

GEOS-Chem v8-03-01

• Domain:Domain: Globe Globe• Horizontal Grid Spacing: 2 ° x 2.5°Horizontal Grid Spacing: 2 ° x 2.5°• Horizontal Coordinate:Horizontal Coordinate: Lat x Lon Lat x Lon• Vertical Grid Spacing:Vertical Grid Spacing: 54 layers 54 layers • Simulation Period:Simulation Period: 2005- 2005-

20082008• Meteorological Input:Meteorological Input: GEOS5 GEOS5

Emissions Summary

Inter-annual Variability of Ozone (Avg JFM) CMAQ BCON

WEST

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5

10

15

20

25

0.00 0.05 0.10O3 Concentration (ppm)

Ele

vati

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(km

)

2005

2006

2007

2008

NORTH

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5

10

15

20

25

0.00 0.05 0.10O3 Concentration (ppm)

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vati

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(km

)

2005

2006

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2008

EAST

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5

10

15

20

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0.00 0.05 0.10O3 Concentration (ppm)

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vati

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(km

)2005

2006

2007

2008

SOUTH

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5

10

15

20

25

0.00 0.05 0.10O3 Concentration (ppm)

Ele

va

tio

n (

km

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2005

2006

2007

2008

9ppb10 ppb

Inter-annual Variability of Ozone (Avg AMJ) CMAQ BCON

WEST

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5

10

15

20

25

0.00 0.05 0.10O3 Concentration (ppm)

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(km

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2005

2006

2007

2008

NORTH

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5

10

15

20

25

0.00 0.05 0.10O3 Concentration (ppm)

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(km

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2005

2006

2007

2008

EAST

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5

10

15

20

25

0.00 0.05 0.10O3 Concentration (ppm)

Ele

vati

on

(km

)2005

2006

2007

2008

SOUTH

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5

10

15

20

25

0.00 0.05 0.10O3 Concentration (ppm)

Ele

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tio

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km

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2005

2006

2007

2008

All less than 5 ppb

Inter-annual Variability of Ozone (Avg JAS) CMAQ BCON

WEST

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15

20

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0.00 0.05 0.10O3 Concentration (ppm)

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2005

2006

2007

2008

NORTH

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5

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0.00 0.05 0.10O3 Concentration (ppm)

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(km

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2006

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2008

EAST

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0.00 0.05 0.10O3 Concentration (ppm)

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(km

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2006

2007

2008

SOUTH

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25

0.00 0.05 0.10O3 Concentration (ppm)

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2006

2007

2008

All less than 5 ppb

Inter-annual Variability of Ozone (Avg OND) CMAQ BCON

WEST

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20

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0.00 0.05 0.10O3 Concentration (ppm)

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2005

2006

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2008

NORTH

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0.00 0.05 0.10O3 Concentration (ppm)

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(km

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2006

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2008

EAST

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0.00 0.05 0.10O3 Concentration (ppm)

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(km

)2005

2006

2007

2008

SOUTH

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0.00 0.05 0.10O3 Concentration (ppm)

Ele

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km

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2005

2006

2007

2008

12ppb

Development of GEOS-Chem to CMAQ IC/BCs Module (Geo2CMAQ)

• Newest version – 2010 (version 2.2)

– Tropopause determining algorithm to remove stratospheric effects from GEOS-Chem

– Update to the newest version of GEOS-Chem v8-03-01

– Add CB05-AE5 conversion table

Introducing the concept of tropopause

• Imaginary layer that separates between stratosphere and troposphere.

• Abrupt change of physical phenomenon

• Three different ways to define tropopuase

– Temperature1 (1937) => Thermal tropopuase

– PV2 (1959) => Dynamical tropopause

– Ozone3 (1995) => Ozone tropopause1 1Stohl A., et al., J. Geophys. Res. (2003)2Shapiro (1980), WMO (1986)3Bethan, S., et al, J. R. Meteorol. Soc (1995)

Vertical Profile and Tropopause Determining Algorithm

• Determining tropopause based on the dynamical searching on maximum rate of change of slope

• Abrupt change of ozone and CO concentrations occurred

• Each grid in downscaling has its own ozone tropopause height, so temporal and spatial integrity can be conserved…

(ppm)

0 2 4 6 8

Ele

vatio

n (k

m)

0

10

20

30

40

40200-30-60

0.00 0.16

Ozone TemperatureCO

Ozone Concentration (ppmv) (Degree C)

Thermal TropopauseOzone Tropopause

Dyn

amic

al T

ropo

paus

e

Ozone Concentration (ppmv)

(ppmv)

OzoneCO Temp.

July 25, 2002 (Trinidad Head, CA)

(Degree C)

Geo2CMAQ Conversion tool

3Lam, Y. F. and  J. S. Fu (2009)., Atmos. Chem. Phys., 10, 4013-4031, doi:10.5194/acp-10-4013-2010

CB05-AE5 Conversion Table

??The ratio between Aged SOA and Non-aged SOA??

CMAQ Model Configurations

CMAQ V4.7

• Meteorological Input Meteorological Input MM5 V3.7MM5 V3.7• Domain:Domain: CONUSCONUS• Horizontal Grid Spacing: Horizontal Grid Spacing: 36 km 36 km • Horizontal Coordinate:Horizontal Coordinate: LCCLCC• Vertical Grid Spacing:Vertical Grid Spacing: 24 layers 24 layers • Simulation Period:Simulation Period: 20052005• IC/BC:IC/BC: GEOS-Chem 2005GEOS-Chem 2005

Two IC/BC scenarios were performed:

1. 24 Layer IC/BC using 24-layer MCIP product

2. 24 Layer IC/BC using average layer collapsing technique from 34-layer MCIP & 34-layer IC/BC

24-layer Vs 34-layer (sample point)

WEST

0

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0.00 0.05 0.10

Ozone (ppm)

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24L

34L

NORTH

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0.00 0.05 0.10

Ozone (ppm)

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24L

34L

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Ozone (ppm)

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34L

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24L

34L

The major effect will be on 23rd and 24th layer

Comparison of “24L” – “24L=>34L” Surface Concentration

JAN – O3 JUL – O3

JAN – SO2 JUL – SO2

Summary

1. The GEOS2CMAQ program improves the downscaling process for generating GEOS-Chem IC/BC. In this study, total of four years of GEOS-Chem simulation have been performed

– The variability of average seasonal background boundary concentration of ozone is about 10–12 ppbv

– Mostly occurred at the upper level of North and South bounds

2. The newt approach for generating the IC/BC using full sigma level gives a better data portability. It also makes it easier to share IC/BC data with other researchers.

• Only required very limited processing. • It only changes the surface ozone level by less than

0.25 ppb from original method.

3. We are in the progress to construct a website to share the IC/BC files, which we have on those 4 years.

Acknowledgement

• USEPA’s STAR and GCAP (phase 1 and phase 2) funding supports

Q & A

Thank you!