Supermodel, Supermodel,Can I Breathe Tomorrow?

Talat Odman* and Yongtao HuGeorgia Institute of Technology

School of Civil & Environmental Engineering

Georgia Air Quality & Climate SummitMay 4, 2006

Air Quality Forecasting

• Increasing interest in day-to-day air quality – Public awareness– Short-term local management strategies

• Forecasts are produced using various techniques– Persistence– Simple empirical “rules-of-thumb”– Statistical regression– Complex heuristics

• In Atlanta, since 1996– Panel of experts produce a forecast

• Recently, forecasts based on numerical models have emerged

Numerical Forecasting Efforts

• NOAA/EPA– Eta-CMAQ modeling system

• MCNC/BAMS– MM5-MAQSIP-RT modeling system

• NCAR/NOAA– WRF-Chem modeling system

• Canadians– GEM-CHRONOS modeling system

Goal

• To provide accurate “fine-scale” local forecasts sufficiently in advance for planning purposes

• NOAA/EPA’s target is to issue nationwide 2-day forecasts with 2.5-km resolution 10 years.– Davidson, P. M. et al., “National Air Quality

Forecasting Capability,” February 14, 2005.

• We want to get there (and beyond) locally much faster.– Longer periods– Finer resolution– Viability of strategies to avoid bad episodes

• WRF for meteorology

• SMOKE for emissions

• CMAQ for chemistry and transport

Our Modeling System

Modeling Domain and Grids

• Three grids:– 36-km (72x72)– 12-km (72x72)– 4-km (99x78)

• Horizontal domains are slightly larger for WRF

• 34 vertical layers used in WRF

• 13 layers in CMAQ

Current Operation

• WRF is driven by NAM (formerly ETA) data– 3 ½ -day NAM data available every 6 hours (00, 06,

12, 18Z)

• Tomorrow’s forecast by 10 a.m. today– Friday’s operation started on Tuesday night

• We simulate:– 3 days over the 36-km grid using 00Z NAM and IC

from previous cycle and “clean” BC– 2 ½ days over the 12-km grid using 12Z NAM and

IC/BC from 36-km– 28 hours over the 4-km using 12Z NAM and IC/BC

from 12-km

• Mostly automated, employ 2 people and 6 CPUs• The product is a 24-hr forecast once per day

Emission Forecasting

• Our goal is to use most up-to-date emissions inventories

• We projected the NEI-2002 emissions to 2006 using growth and control factors – EGAS model– NOx SIP controls

• We use monthly-averaged data for major point sources and wild fires

• We forecast mobile emissions– Emission factors use the episode (3, 2 ½ or 1 day)

average temperature

• We forecast biogenic emissions using summertime leaf indexes

Today’s & Tomorrow’s Forecasts

Metropolitan Atlanta

• Today:– Peak 1-hr ozone will be 65 ppb at Gwinnett at 2 p.m.– Peak 1-hr PM2.5 will be 29.6 g m-3 at Gwinnett at 8

a.m.

• Tomorrow:– Peak 1-hr ozone will be 65 ppb at Yorkville at 2 p.m.– Peak 1-hr PM2.5 will be 32.0 g m-3 at South DeKalb

at 8 a.m.

• http://www.ce.gatech.edu/research/forecast/

Yesterday’s Forecast

Peak 1-hr Ozone & PM2.5

• Predicted peak ozone – Conyers– 4 p.m.– 72 ppb

• Predicted peak PM2.5

– South DeKalb

– 8 a.m.

– 23.6 g m-3

• Observed– Conyers

– 4 p.m. – 66 ppb

(9% over prediction)

• Observed– Confederate Ave.

(nearest monitor)

– 10 a.m. (2 hrs in advance)

– 29.5 g m-3 (20% under prediction)

12-km Ozone at 4 p.m.

Ozone at Conyers on 5/3/2006

O3 at CONYERS on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

Ozone in Metro AtlantaO3 at CONFDAVE on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

O3 at DOUGLASV on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

O3 at GWINNETT on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

O3 at KENNESAW on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

PM2.5 at South DeKalb

PM2.5 at SDEKALB on 5/3/2006

0.0

20.0

40.0

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80.0

100.0

120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

3)

4-km

12-km

Obs.

PM2.5 in Metro AtlantaPM2.5 at CONFDAVE on 5/3/2006

0.0

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80.0

100.0

120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

3)

4-km

12-km

Obs.

PM2.5 at GWINNETT on 5/3/2006

0.0

20.0

40.0

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120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

3)

4-km

12-km

Obs.

PM2.5 at MCDONOUGH on 5/3/2006

0.0

20.0

40.0

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100.0

120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

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12-km

Obs.

PM2.5 at NEWNAN on 5/3/2006

0.0

20.0

40.0

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80.0

100.0

120.0

1 5 9 13 17 21

Time (EDT)

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Obs.

Other Places in Georgia

AthensO3 at ATHENS on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

PM2.5 at ATHENS on 5/3/2006

0.0

20.0

40.0

60.0

80.0

100.0

120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

3)

4-km

12-km

Obs.

AugustaO3 at AUGUSTA on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

PM2.5 at AUGUSTA on 5/3/2006

0.0

20.0

40.0

60.0

80.0

100.0

120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

3)

4-km

12-km

Obs.

ColumbusO3 at COLAIRPT on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

PM2.5 at COLAIRPT on 5/3/2006

0.0

20.0

40.0

60.0

80.0

100.0

120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

3)

4-km

12-km

Obs.

MaconO3 at MACON-SE on 5/3/2006

0.000

0.060

0.120

0.180

0.240

1 5 9 13 17 21

Time (EDT)

O3

(pp

m)

4-km

12-km

Obs.

PM2.5 at MACON-SE on 5/3/2006

0.0

20.0

40.0

60.0

80.0

100.0

120.0

1 5 9 13 17 21

Time (EDT)

PM

2.5 (

g/m

3)

4-km

12-km

Obs.

Next Steps

• Find support– Many thanks to Georgia Tech Forecasting Group and

GA DNR for seeding this effort– Need at least 5x in FY-07

• Objectives:– Continue the operation– Set up a user-friendly web site– Archive the data for future use– Extend the domain of coverage– Increase the resolution– Elongate the forecast period– Issue a daily update– Start an evaluation program– Improve the accuracy