university of california at riverside fire plume rise · university of california at riverside fire...

Center for Environmental Research and Technology/Environmental Modeling

University of California at Riverside

Fire Plume RiseWRAP (FEJF) Method vs. SMOKE Briggs

(SB) Method

Mohammad Omary, Gail TonnesenWRAP Regional Modeling CenterUniversity of California Riverside

Zac AdelmanCarolina Environmental Program

University of North Carolina

Fire Emissions Joint Forum Meeting, October 17-18, 2006, Spokane, WA



Fire Plume Rise Modeling Project Status

• Today’s Presentation– Project Objectives– Plume Rise Modeling Methods– Fire Events Modeled– Results– Summary



Acknowledgments

• Tom Moore and FEJF – project design• Air Sciences - Emissions Inventory



Fire Plume Rise Modeling Project Objectives

Compare the plume rise and the vertical emissions distribution for fires, using to methods:

1. The FEJF Approach2. The SMOKE-Briggs Approach



Model vertical layer structure

• CMAQ has 19 vertical layers:– Layer 1: 0 - 36 m– Layer 2-5: 36 - 220 m– Layer 6-10: 220 - 753 m – Layer 11-14: 753 - 1828 m– Layer 15-16: 1828 - 3448 m– Layer 17-19: 3448 - 14,662 m



Plume Tophour = (BEhour)2 * (BEsize)2 * Ptopmax

Plume Bottomhour = (BEhour)2 * (BEsize)2 * Pbotmax

Layer1 Fractionhour = 1 – (BEhour * BEsize)

BEsize = fire size-dependent buoyancy efficiency Behour = hourly buoyancy efficiency Pbotmax = maximum height of the plume bottomPtopmax = maximum height of the plume top

BEsize, Ptopmax Pbotmax, and BEhour are provided in the FEJF Phase II fire report (Air Sciences, Inc., 2006).

1. FEJF ApproachPlume Rise Modeling Methods



Plume Buoyancy Efficiency, F (m4/s3), as follows.F = Q * 0.00000258Q = Heat Flux (btu/day),

Buoyant Efficiency (BEsize)BEsize = 0.0703 * ln(acres) + 0.03

Smoldering Fraction (Sfract)Sfract = 1 – BE size

NOTE: possible bug in implementing smoldering fraction in SMOKE. We expect a larger fraction of emissions in layer 1 in SB.

2. SMOKE-Briggs Approach (SB)



Heat Flux from FEPS

• Fire Emissions Productions Simulator (FEPS) was used to determine heat flux:– FEPS was developed by Anderson et al.

http://www.fs.fed.us/pnw/fera/feps/– User specifies the fire name, location, start date, end date,

size, fuel type and other properties.– FEPS calculates the hourly emissions and heat release.– Uncertainty in specifying fire variables in FEPS might

affect heat release estimate.– Not available in batch mode so difficult to use FEPS in SB.



Fire Type State Date

Fire Size(Acres)

Daily Emissions (tons/day)Heat Flux (btu/day)CO PM2.5 NOx VOC

WFU1 CO July 14 850 3382.6 282.08 72.57 159.18 82,530,000,000

RX2 AZ Nov. 07 2577 3988.1 332.58 85.56 187.68 268,320,000,000

WF3 AZ June 30 9860 19804.3 1651.5 424.9 931.97 1,036,600,000,000

RX OR Sep. 24 1000 173.4 14.46 3.72 8.16 300,030,000

WF OR Aug. 03 7885 25,293.8 2,109.3 542.6 1,190.3 2,237,008,255,600

1WFU= wildland fire use 2RX=prescribed fire 3WF=wildfire

Fire Events



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Time (h)

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ght (

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. Fra

c. in

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er 1

PBOTPTOPLAY1F

FEJF fire CharacteristicsOregon Prescribed Fire

PBOT = Plume BottomPTOP = Plume TopLAY1F = Emissions fraction in Layer 1



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FEJF fire CharacteristicsOregon Wild Fire



Hourly Emissions per LayerColorado Wild Fire

1 3 5 7 911 13 15 17 19 21 23 L1 L4 L7 L1

0 L13 L1

6

0

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CO

Ton

s/h

TimeLayer

FEJF Plume riseL1L2L3L4L5L6L7L8L9L10L11L12L13L14L15L16L17L18

Tot

1 3 5 7 911 13 15 17 19 21 23 L1

L4

L7 L10

0

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Time

Layer

SB Plume Rise

L1L2L3L4L5L6L7L8L9L10L11L12

Tot



FEJF Profile

050

100150200250300350400450500550600

1 3 5 7 9 11 13 15 17 19 21 23

Time (h)

Tons

/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L18L17L16L15L14L13L12L11L10L9L8L7L6L5L4L3L2L1Max LHSB Profile

050

100150200250300350400450500550600

1 3 5 7 9 11 13 15 17 19 21 23

Time (h)

Ton

s/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L12L11L10L9L8L7L6L5L4L3L2L1Max LH

Hourly Emissions DistributionColorado Wild Fire



1 3 5 7 911 13 15 17 19 21 23

0

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CO

Ton

s/h

TimeLayer

FEJF Plume riseL1L2L3L4L5L6L7L8L9L10L11L12L13L14L15L16L17L18

Tot

1 3 5 7 911 13 15 17 19 21 23 L1 L2 L3 L4 L5 L6 L7 L8 L9 L1

0L1

1To

t

0

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200

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700

CO

Ton

s/h

Time

Layer

SB Plume rise

L1L2L3L4L5L6L7L8L9L10L11

Tot

Hourly Emissions per LayerArizona Prescribed Fire



FEJF Profile

050

100150200250300350400450500550600650700

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time (h)

Ton

s/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L18L17L16L15L14L13L12L11L10L9L8L7L6L5L4L3L2L1Max LH

SB Profile

050

100150200250300350400450500550600650700

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time (h)

Tons

/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L11

L10

L9

L8

L7

L6

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Max LH

Hourly Emissions DistributionArizona Prescribed Fire



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CO

Ton

s/h

Time

Layer

FEJF Plume rise

L1L2L3L4L5L6L7L8L9L10L11L12L13L14L15L16L17L18

Tot

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CO

Ton

s/h

Time

Layer

SB Plume rise L1L2L3L4L5L6L7L8L9L10L11L12L13L14L15

Tot

Hourly Emissions per LayerArizona Wild Fire



FEJF Profile

0

500

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3500

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time (h)

Tons

/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)


SB Profile

0

500

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time (h)

Ton

s/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L15L14L13L12L11L10L9L8L7L6L5L4L3L2L1Max LH

Hourly Emissions DistributionArizona Wild Fire



0

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CO

Ton

s/h

Time Layer

FEJF Plume riseL1L2L3L4L5L6L4L8L9L10L11L12L13L14L15L16L17

Tot

1 3 5 7 9 11 1315

17 1921

23

0

5

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CO

Ton

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TimeLayer

SB Plume rise

L1L2L3L4

Tot

Hourly Emissions per LayerOregon Prescribed Fire



FEJF Profile

0

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time (h)

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040080012001600200024002800320036004000440048005200

Max

Lay

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iegh

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)

L17L16L15L14L13L12L11L10L9L8L7L6L5L4L3L2L1Max LH

SB Profile

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Hourly Emissions DistributionOregon Prescribed Fire



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CO

Ton

s/h

TimeLayer

FEJF Plume rise

L1L2L3L4L5L6L7L8L9L10L11L12L13L14L15L16L17L18

Tot

1 3 5 7 9 11 13 15 17 19 21 23

0

500

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CO

Ton

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TimeLayer

SB Plume rise L1L2L3L4L5L6L7L8L9L10L11L12L13L14L15

Tot

Hourly Emissions per LayerOregon Wild Fire



FEJF Sky Profile

0

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2400

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time (h)

Tons

/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)


SB Profile

0

500

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1500

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Time (h)

Ton

s/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L15L14L13L12L11L10L9L8L7L6L5L4L3L2L1Max LH

Hourly Emissions DistributionOregon Wild Fire



0

0.1

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daily

frac

tion

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

CO

_FEJ

F

CO

_SB

AZ_

FEJF

_WF

AZ_

SB_W

F

AZ_

FEJF

_RX

AZ_

SB_R

X

OR

_FEJ

F_W

F

OR

_SB

_WF

OR

_FEJ

F_R

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OR

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_RX

layer

CO_FEJFCO_SBAZ_FEJF_WFAZ_SB_WFAZ_FEJF_RXAZ_SB_RXOR_FEJF_WFOR_SB_WFOR_FEJF_RXOR_SB_RX

Daily Emissions Fractions per Layer

CO FEJF: 45% in surface layer, 45% above 2462 m.

CO SB: most emission between 200 - 1000 m.



Results

1. The FEJF approach places a large fraction of the emissions in the surface layer, and the plume with the remaining emissions are consistently located at higher layers compared to the SB approach.

2. The plume bottom in FEJF depend on the fire size. It can be as high as several thousand meters above the first layer. In SB the plume bottom is always above the first layer.

3. On daily basis, most of the emissions are in the first layer in FEJF, while in SB most of the emissions in the mid to upper layers.



Conclusions• The SB approach seems unrealistic since smoldering

emissions should be located in the first layer.• Since emissions occur during the day time when the boundary

layer tends to be well mixed, model results might be insensitive to the vertical location of emissions within the boundary layer.– To the extent that the FEJF approach locates emissions above the

boundary layer, it might have smaller near field impact and greater long range transport.

– If fires occur at times when the boundary is shallow or poorly mixed, the FEJF approach might have a greater near field impact and less long range transport.



Conclusions (2)• Air quality modeling using CMAQ or CAMx is needed to

determine of the two approaches would have significantly different air quality impacts, however, the current approach using FEPS is not feasible to model a large number of events.

• Because the differences in near field versus long range transport might depend on the meteorology conditions, it would be necessary to model a large variety of conditions to determine if the choice of FEPS or SB results in consistently different visibility impacts.

• SB approach would have greater near field impacts than FEJF if SMOKE is modified to locate a larger smoldering fraction in layer 1.

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