Georgia Institute of Technology

Forecasting the Impacts of Wildland Fires

Yongtao Hu1, William Jackson2, M. Talat Odman1 and Armistead G. Russell1

1School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia

2USDA Forest Service, Asheville, North Carolina

Presented at the 6th Annual CMAS Conference, October 2nd, 2007

Georgia Institute of Technology

Wild land Fires and Air Quality

Wild land fire (wild and prescribed fires) burned ~9 million acres nationwide in US each year during the past three years.

Burning of wild land vegetation increases emissions of PM2.5, CO, VOC, NOx …, which impact air quality, visibility and potentially public health.

A severe wild land fire could cause rapid increases of both PM2.5 and O3 to extremely high levels at populated area and cause exposures to unhealthy air for several hours or even days. Such as those hit Atlanta metro area with thick smoke clouds this year:

To what degree can we forecast wild-land-fire-impacts on air quality by adopting current operational air quality forecasting system?

The prescribed fires on February 28, 2007 in Jasper County Georgia. The Georgia-Florida wildfires lasting from April through May.

Georgia Institute of Technology

Hi-Res Air Quality Forecasting SystemServing Metro-Atlanta Area since 2006

CMAQ

SMOKE

Emission Inventory

WRF

NAM 84-hr Forecast

Forecast Product

MeteorologyEmissions

Air Quality

Georgia Institute of Technology

36-km

12-km

4-km

Hi-Res Modeling Domains

Georgia Institute of Technology

Hi-Res Cycle00Z 45Z 77Z

36- & 12-km ramp up simulation 12- & 4-km forecast

8pm 0am0am0am0amForecast Day

Start Job Finish Job Release Product

What could be done?

For prescribed burning, the air quality forecast ahead of the actual igniting would help plan and conduct burns.

For existing/ongoing wildfires, the air quality forecast would warn people to avoid unhealthy air exposures at the following days.

Hi-Res cycle allows sufficient time for extra efforts.

Georgia Institute of Technology

Estimate Emissions of Potential Fires

Using models: the Fire Emission Production Simulator (FEPS) and the Consume 3.0 (http://

www.fs.fed.us/pnw/fera/research/smoke/consume/index.shtml )

Prescribed fire: collect pre-burning information from the burning plans prepared in advance.

acreage of planned burning area, approximate locations, fuel load descriptions, igniting method and operation schedules …

Existing/ongoing wild fire: determine the most likely fire locations on the following days according to the analysis of forecast meteorological conditions combined with the information on previous days’ burning locations.

Then collect and estimate other fire information: approximate acreage of burning area, fuel consumption and expected fire temperatures …

Allocate estimated potential fire emissions to the corresponding Hi-Res grid cells according to the geographical information.

Georgia Institute of Technology

Wild-Land-Impacts on Air Quality

One way to calculate the air quality impacts of a fire is to run two simulations:Run (1): “typical” emissions default in Hi-ResRun (2): estimated potential fire emissions added

in and to take their difference:

Impact = Air Quality (2) – Air Quality (1). A more efficient way is to estimate the contribution

of the fires by calculating emission sensitivities with the Decoupled Direct Method (DDM) provided by the Hi-Res system.Requires a single model run with potential fire emissions

added in.

Georgia Institute of Technology

Application to prescribed fire: forecast and hindcast the February 28th, 2007 episode

Forecast: to test the predictive capability of this system.

Forecast meteorology

Emissions estimated from pre-burning information

Hindcast: to identify key weaknesses in the system.

Re-analysis data (through FDDA) to predict the meteorology

Post-burning information to estimate emissions

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Atlanta

Smoke Detected by Geostationary Satellite(1:15-1:45 pm EST on February 28th, 2007 )

Georgia Institute of Technology

34.2

34.0

33.8

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-85.0 -84.5 -84.0 -83.5

ASACA SEARCH SLAMS PM SLAMS O3 urban area boundary primary roads prescribed burning sites

Atlanta

NewnanFayetteville

McDonough

ConyerWalton

Athens

Fort YargoGwinnett

Kennesaw

YorkvilleFS8

South DekalbFort McPherson

Confederate

Jefferson St.

Ambient Monitoring and Prescribed Burning Sites

Georgia Institute of Technology

160

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g/m

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Confederate

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Walton160

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S. Dekalb

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2/27/07 2/28/07 3/1/07 3/2/07

StartTime (EST)

Newnan

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g/m

3

McDonough

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3

Gwinnett

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3

Athens

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3

Jefferson St.

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Yorkville

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Fire Station #8 160

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Ft. McPherson

Hourly PM2.5

Mass

Georgia Institute of Technology2.0

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m

2/27/2007 2/28/2007 3/1/2007 3/2/2007

StartTime (EST)

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YorkvilleGwinnettNewnanFayettevilleDouglasville

(b)

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ConfederateConyerMcDonoughSouthDekalbJeffersonKennesaw

(a)

Hourly Ozone Concentrations

Georgia Institute of Technology

PM Impact of the Oconee NF and Piedmont NWR Fires

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Observed and Predicted Max. Concentration and Predicted Max. Impact from the Fires within Atlanta Urban Area

0.00

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12 15 18 21 24

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Forecast

Contribution from fire

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12 15 18 21 24

Hour (EST)

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2.5

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PM2.5

Observed

•Sensitivity analysis has shown that observed ozone peaks can only be reached at 5 times typical biogenic VOC emissions from burning areas. Bursts of fire-induced isoprenoid (isoprene and monoterpenes) emissions are reported in the literature.

Georgia Institute of Technology

Organic Matter to PM2.5 Ratios

0.200

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1.000

12 15 18 21 24

Hour (EST)

Rat

io o

f OM

vs.

PM

2.5

Forecast

Hindcast

Observed

Smoke hit Atlanta at hour 17

•Increased VOC emissions also make up part of missing secondary organic aerosol (SOA). Evaporation and re-condensation of leaf surface wax may be another source of SOA as suggested by GC/MS analysis. Also background primary OM from other fires missing in the “typical” inventory.

Georgia Institute of Technology

1-hr Exposures to Ambient PM2.5

0

200

400

600

800

1000

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12 15 18 21 24

Hour (EST)

Pop

ulat

ion

(in

thou

sand

s)

Forecast

Hindcast

35 ug m-3

65 ug m-3

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Forecast, Hindcast and Observed Plumes

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Application to wild fires: the May 18th-23th, 2007 episode of Georgia-Florida wildfires

MODIS aerosol optical depth (AOD) on May 21st (L) and 22nd (R), 2007

Observed Hourly PM2.5

G-F fires plume reached Atlanta after long-range transport through Alabama under easterly winds on 21st that turned to westerly on 22nd.

0255075

100125150175200225250275300325350375

5/21/0712:00

5/21/0716:48

5/21/0721:36

5/22/072:24

5/22/077:12

5/22/0712:00

5/22/0716:48

5/22/0721:36

Time (EST)

PM

2.5

(ug/

m3)

Athens

Columbus

Confederate

Gwinnett

Macon

McDonough

Newnan

South Dekalb

Walton

Yorkville

http://idea.ssec.wisc.edu/Data obtained from

http://www.air.dnr.state.ga.us/amp/

Georgia Institute of Technology

Simulated period: May 18 – 23, 2007 Preliminary Results on May 22

Missed Atlanta

Wildfire Impacts on Hourly PM25

•Possible reasons could be the absence of the surface thermal changes induced by the fire from the meteorological model and the coarse vertical resolution in CMAQ above 1-km from the ground.

Georgia Institute of Technology

Summary

We have developed and tested a modeling system to forecast wildland-fire-impacts on air quality in Atlanta, Georgia.

The application to forecast the prescribed fires on February 28, 2007 was successful and indicates that the fires could be reasonably well estimated using the system. The “forecast” predictions are in good agreement with observations, though the hindcast improves significantly on timing and location.

More efforts are needed to improve the capability of the system to simulate wildfires.