center for environmental research and technology/environmental modeling university of california at...

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 Tonnesen

WRAP Regional Modeling Center

University of California Riverside

Zac Adelman

Carolina 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 Approach

2. 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 bottom

Ptopmax = 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 Approach

Plume Rise Modeling Methods



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



0

1000

2000

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6000

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)

Hei

ght

(m)

0

0.2

0.4

0.6

0.8

1

1.2

Em

is. F

rac.

in L

ayer

1

PBOT

PTOP

LAY1F

FEJF fire CharacteristicsOregon Prescribed Fire

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



0

1000

2000

3000

4000

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6000

7000

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)

Hei

ght

(m)

0

0.2

0.4

0.6

0.8

1

1.2

Em

is. F

rac.

in L

ayer

1

PBOT

PTOP

LAY1F

FEJF fire CharacteristicsOregon Wild Fire



Hourly Emissions per Layer Colorado Wild Fire

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

1 L4 L

7 L10 L

13 L16

0

100

200

300

400

500

600

CO

Ton

s/h

Time

FEJF Plume rise

L1L2L3L4L5L6L7L8L9L10L11L12L13L14L15L16L17L18

Tot

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

1 L4 L

7 L10

0

100

200

300

400

500

600

Time

SB Plume Rise

L1

L2

L3

L4

L5

L6

L7

L8

L9

L10

L11

L12

Tot



FEJF Profile

050

100150200250300350400450500550600

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

Time (h)

To

ns/

h

0500100015002000250030003500400045005000550060006500700075008000

Ma

x L

ay

er H

ieg

ht

(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

)

L12

L11

L10

L9

L8

L7

L6

L5

L4

L3

L2

L1

Max LH

Hourly Emissions Distribution Colorado Wild Fire



1 3 5 7 911 13 15 17 19 21 23

0

100

200

300

400

500

600

700

CO

Ton

s/h

Time

FEJF Plume rise

L1

L2

L3

L4

L5

L6

L7

L8

L9

L10

L11

L12

L13

L14

L15

L16

L17

L18

Tot

1 3 5 7 911 13 15

1719

21

23 L1 L2 L3 L4 L5 L6 L7 L8 L9

L10 L11 Tot

0

100

200

300

400

500

600

700

CO

Ton

s/h

Time

SB Plume rise

L1

L2

L3

L4

L5

L6

L7

L8

L9

L10

L11

Tot

Hourly Emissions per Layer Arizona Prescribed Fire



FEJF Profile

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

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

)

L18

L17

L16

L15

L14

L13

L12

L11

L10

L9

L8

L7

L6

L5

L4

L3

L2

L1

Max 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)

Ton

s/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L11

L10

L9

L8

L7

L6

L5

L4

L3

L2

L1

Max LH

Hourly Emissions Distribution Arizona Prescribed Fire



0

500

1000

1500

2000

2500

3000

CO

Ton

s/h

Time

FEJF Plume rise

L1

L2

L3

L4

L5

L6

L7

L8

L9

L10

L11

L12

L13

L14

L15

L16

L17

L18

Tot

0

500

1000

1500

2000

2500

3000

3500

CO

Ton

s/h

Time

SB Plume rise L1

L2

L3

L4

L5

L6

L7

L8

L9

L10

L11

L12

L13

L14

L15

Tot

Hourly Emissions per Layer Arizona Wild Fire



FEJF Profile

0

500

1000

1500

2000

2500

3000

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)

Ton

s/h

0500100015002000250030003500400045005000550060006500700075008000

Max

Lay

er H

iegh

t (m

)

L18L17L16L15L14

L13L12L11L10L9L8L7L6L5L4

L3L2L1Max LH

SB Profile

0

500

1000

1500

2000

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3000

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)

Ton

s/h

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5500

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Max

Lay

er H

iegh

t (m

)

L15

L14L13

L12L11

L10L9

L8

L7L6

L5L4

L3L2

L1Max LH

Hourly Emissions Distribution Arizona Wild Fire



0

5

10

15

20

25

30

CO

Ton

s/h

Time

FEJF Plume riseL1L2L3L4L5L6L4L8L9L10L11L12L13L14L15L16L17

Tot

13 5

79

1113

1517

1921

23

0

5

10

15

20

25

30

CO

Ton

s/h

Time

SB Plume rise

L1

L2

L3

L4

Tot

Hourly Emissions per Layer Oregon Prescribed Fire



FEJF Profile

0

5

10

15

20

25

30

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

040080012001600200024002800320036004000440048005200

Max

Lay

er H

iegh

t (m

)

L17L16L15L14L13L12L11L10L9L8L7L6L5L4L3L2L1Max LH

SB Profile

0

5

10

15

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25

30

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

0

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2800

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4400

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Max

Lay

er H

iegh

t (m

) L4

L3

L2

L1

Max LH

Hourly Emissions Distribution Oregon Prescribed Fire



0

500

1000

1500

2000

2500

3000

3500

4000

4500

CO

Ton

s/h

Time

FEJF Plume rise

L1L2L3L4L5L6L7L8L9L10L11L12L13L14L15L16L17L18

Tot

1 3 5 7 9 11 13 15 17 1921 23

0

500

1000

1500

2000

2500

3000

3500

4000

4500

CO

Ton

s/h

Time

SB Plume rise L1

L2

L3

L4

L5

L6

L7

L8

L9

L10

L11

L12

L13

L14

L15

Tot

Hourly Emissions per Layer Oregon Wild Fire



FEJF Sky Profile

0

400

800

1200

1600

2000

2400

2800

3200

3600

4000

4400

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

0

500

1000

1500

2000

2500

3000

3500

4000

4500

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

0

500

1000

1500

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2500

3000

3500

4000

4500

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5500

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6500

7000

7500

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Max

Lay

er H

iegh

t (m

)

L15

L14

L13

L12

L11

L10

L9

L8

L7

L6

L5

L4

L3

L2

L1

Max LH

Hourly Emissions Distribution Oregon Wild Fire



0

0.1

0.2

0.3

0.4

0.5

0.6

dail

y fr

acti

on

12

34 5

67

8 910

1112 13

1415

16 1718

CO

_FE

JF

CO

_SB

AZ

_FE

JF_W

F

AZ

_SB

_WF

AZ

_FE

JF_R

X

AZ

_SB

_RX

OR

_FE

JF_W

F

OR

_SB

_WF

OR

_FE

JF_R

X

OR

_SB

_RX

layer

CO_FEJF

CO_SB

AZ_FEJF_WF

AZ_SB_WF

AZ_FEJF_RX

AZ_SB_RX

OR_FEJF_WF

OR_SB_WF

OR_FEJF_RX

OR_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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