Modeling In-Canopy Dispersion of Pheromones Using a Puff Model

Modeling In-Canopy
Dispersion of Pheromones
Using a Puff Model
Presenter: Tara Strand
AirFire Research Team, Pacific Northwest Research Station, USDA Forest Service
Co-Authors: Brian Lamb, Harold Thistle,
Gene Allwine, Holly Peterson, and Steve Seybold

Overall Goal: Simulate Pheromone Dispersion
• Improve our ability to simulate tracer gas movement and
spread under a forest canopy
– Instantaneous puff dispersion model
Objective: Simulate pheromone concentration
fluctuations on all temporal scales
• Simulate time averaged and instantaneous
concentrations
– Evaluate the model using SF 6 data collected during recent
surrogate pheromone transport studies
(Thistle et al., 2004)
• Lodgepole pine site, Montana, July 2000
• Ponderosa pine site, Oregon, June 2001

Surrogate Pheromone
Transport Studies

Description of Model
• Lagrangian
• Three-dimensional
• Instantaneous puff dispersion model
• Derived from meandering plume model
(Peterson et al., 1990)
• Simulates pheromone plume transport and dispersion
• Produces output at different temporal scales
– Time-averaged pheromone concentrations for the entire
domain or at specified receptors
– Instantaneous pheromone concentrations at a specified
receptor

Puff Release
• 1 puff released every 1 s
– Advected downwind using sonic
data as input
• u, v, and w wind components
• Spread of puff is assumed
Gaussian
– Calculated from turbulence data
– Isotropic in the horizontal
Y Distance (m)
X Distance (m)
• 30 minute simulation time
• Domain
– 66 m X 66 m X 10 m
– 0.5 m X 0.5 m X 0.5 m (grid
size)

m&m&m&m&
The Model: Guassian Puff Equation
C
i
C
ip
N
= ∑ C
ip
P = 1
=
m&
2 σ σ
2
z r
π
where,
2π
⎡ ⎛
⎢ ⎜ ⎛
⎢ ⎜
⎜ r
× exp − 0.5
⎢ ⎜
⎜ σ
⎣ ⎝
⎝ r
2 ⎞⎤
⎡ ⎛
2 ⎞ ⎛
2 ⎤
⎞
⎞
⎢ ⎜ ⎛ ⎞ ⎜ ⎛ ⎞
⎟
⎟⎥
⎟
⎟⎥
⎢
⎜
⎜ −
⎜
⎜ z + H ⎟
z H
⎟
⎟ + − ⎟
⎥×
exp − 0.5
exp 0.5
⎟
⎟⎥
⎟ ⎢ ⎜
⎜ σ ⎟
⎟ ⎜
⎜ σ ⎟
⎠ ⎥
⎟⎥
⎠ ⎣ ⎝
⎝ z ⎠
⎠ ⎝
⎝ z ⎠
⎦
⎠⎦
• m& = mass (μg) released every second
• r = radial distance from the center of each puff to a
specific receptor point (m)
• z = height from the surface to the receptor (m)
• H = release height (m)
• σ r = horizontal dispersion coefficient of the puff
• σ z = vertical dispersion coefficient of the puff
• N = number of puffs released

Maximum Normalized
Concentrations
10
1
0.1
0.01
Lodgepole Pine
Canopy
0.001
0 5 10 15 20 25 30 35
Distance (m)
Time Averaged
Concentrations
and Distance
Maximum Normalized
Concentrations
10
1
0.1
0.01
Ponderosa Pine
Canopy
0.001
0 5 10 15 20 25 30 35
Distance (m)

Time Averaged Concentrations and Wind Speed
0.90
0.90
Predicted
Predicted
Normalized Concentration
5 m from the Release
0.60
0.30
y = 0.11x -1.17
R 2 = 0.54
Observed
y = 0.10x -1.01
R 2 = 0.63
Normalized Concentration
5 m from the Release
0.60
0.30
y = 0.06x -1.31
R 2 = 0.41
Observed
y = 0.06x -1.00
R 2 = 0.31
0.00
0.0 0.5 1.0 1.5
Wind Speed (ms -1 )
Predicted
Observed
Power (Predicted) Power (Observed)
Lodgepole Pine
Canopy
0.00
0 0.5 1 1.5
Wind Speed (ms -1 )
Predicted
Power (Predicted)
Observed
Power (Observed)
Ponderosa Pine
Canopy

Time Averaged Concentrations and Wind Variance
0.70
0.70
Normalized Concentration
10 m from the Release
0.60
0.50
0.40
0.30
0.20
0.10
Predicted
y = 0.73e -5.20x
R 2 = 0.69
Observed
y = 0.49e -4.31x
R 2 = 0.59
Normalized Concentration
10 m from the Release
0.60
0.50
0.40
0.30
0.20
0.10
Predicted
y = 0.76x 2 - 0.90x + 0.29
R 2 = 0.53
Observed
y = 0.54x 2 - 0.66x + 0.22
R 2 = 0.51
0.00
0.00 0.20 0.40 0.60 0.80
Variance (Radians)
Predicted
Observed
Expon. (Predicted) Expon. (Observed)
0.00
0.00 0.20 0.40 0.60 0.80
Variance (Radians)
Predicted
Observed
Poly. (Predicted) Poly. (Observed)
Lodgepole Pine
Canopy
Ponderosa Pine
Canopy

Time Averaged Concentration Shape
Ponderosa Pine Canopy: June 21, 2001 at 1:00 p.m.
5 m from the Source 10 m from the Source
330
0.09
0
30
330
0.016
0
30
0.06
300
0.012
60
300
0.03
60
285
0.008
0.004
90
270
0.00
90
270
0
120
240
120
255
150
210
150
Simulated
Observed
240
225
185
180
180
210

Time Averaged Concentration Shape
Ponderosa Pine Canopy: June 25, 2001 at 4:00 p.m.
5 m from the Source 10 m from the Source
330
0.09
0
30
330
0.040
0
30
0.06
0.030
300
60
300
0.020
60
0.03
0.010
270
0.00
90
270
0.000
90
240
120
240
120
210
150
Simulated
Observed
210
150
180
180

Instantaneous Concentrations
Lodgepole Pine Site: July 24, 2000, 10:30 a.m.
Surrogate Pheromone (SF6 ppt)
14000
12000
10000
8000
6000
4000
2000
Observed
Simulated
0
0 300 600 900 1200 1500 1800
Time (s)

Lodgepole Pine
Canopy

Application ~ Four Sources: Lodgepole Pine
Distance (m)
130
120
110
100
90
80
70
60
50
40
30
20
10
Normalized SF6
(Surrogate Pheromone)
Concentrations
1.00E-03
4.12E-04
1.70E-04
7.02E-05
2.89E-05
1.19E-05
4.92E-06
2.03E-06
8.38E-07
3.46E-07
1.43E-07
5.88E-08
2.42E-08
1.00E-08
10 20 30 40 50 60 70 80 90 100 110 120 130
Distance (m)

Application ~ Four Sources: Ponderosa Pine
Distance (m)
130
120
110
100
90
80
70
60
50
40
30
20
10
Normalized SF6
(Surrogate Pheromone)
Concentrations
1.00E-03
4.12E-04
1.70E-04
7.02E-05
2.89E-05
1.19E-05
4.92E-06
2.03E-06
8.38E-07
3.46E-07
1.43E-07
5.88E-08
2.42E-08
1.00E-08
50 100
Distance (m)

Results: Instantaneous Concentrations
Distance (m)
130
120
110
100
90
80
70
60
50
40
30
20
10
10 20 30 40 50 60 70 80 90 100 110 120 130
Distance (m)
Concentration
130
120
2.98x10 +02
7.34x10 +01
110
1.81x10 +01
4.46x10 +00
100
1.10x10 +00
2.71x10 -01
90
6.68x10 -02
1.65x10 -02
80
4.06x10 -03
1.00x10 -03
70
60
50
40
1 s at
30
20
60 s
10
ng/m 3 10 20 30 40 50 60 70 80 90 100 110 120 130
Distance (m)
Distance (m)
Concentration
ng/m 3
2.98x10 +02
7.34x10 +01
1.81x10 +01
4.46x10 +00
1.10x10 +00
2.71x10 -01
6.68x10 -02
1.65x10 -02
4.06x10 -03
1.00x10 -03
1 s at
600 s
Distance (m)
130
120
110
100
90
80
70
60
50
40
30
20
10
10 20 30 40 50 60 70 80 90 100 110 120 130
Distance (m)
ng/m 3 130
Concentration
120
2.98x10 +02
7.34x10 +01
1.81x10 +01
4.46x10 +00
1.10x10 +00
2.71x10 -01
6.68x10 -02
1.65x10 -02
4.06x10 -03
1.00x10 -03
110
100
90
80
70
60
50
40
30
20
10
10 20 30 40 50 60 70 80 90 100 110 120 130
1 s at
1200 s
Distance (m)
Distance (m)
Concentration
ng/m 3
2.98x10 +02
7.34x10 +01
1.81x10 +01
4.46x10 +00
1.10x10 +00
2.71x10 -01
6.68x10 -02
1.65x10 -02
4.06x10 -03
1.00x10 -03
30-min.
ave.

Application: Threshold Response
χ
Ph
=
χ
SF
6
Q
SF
6
×
Q
Ph
χ Ph
= Estimated Pheromone concentration
χ SF6 = Measured SF 6 concentration
Q SF6 = SF 6 release rate
Q Ph = Pheromone release rate

Application: Threshold Response
40
Number of Beetles Trapped (Total)
30
20
10
Pheromone Concentrations > 0.02 μg m -3
Attraction to unbaited traps increases
0
0.0001 0.0010 0.0100 0.1000 1.0000
Estimated Pheromone Concentrations based on SF 6 Concentrations (μg m -3 )

Distance (m)
60
50
40
30
20
10
10 20 30 40 50 60
Distance (m)
Ipsdienol Concentrations
ug m-3
N
0.400
0.292
0.213
0.155
0.113
0.083
0.060
0.044
0.032
0.023
0.017
0.012
0.009
0.007
0.005
0.004
0.003
0.002
0.001
0.001
Hypothetical Application: Ponderosa Pine

.
Acknowledgements: Funding
This research was supported by the USDA Forest Service
FHP/FHTET, award No.: 01-CA-11244225-025 and USDA
Forest Service Projects FHTET TD.00.M03 and FHTET
TD.00.MO1
Pacific Southwest Research Station, Chemical Ecology of
Forest Insects Project and by a grant from the Human
Frontier Science Program (#RGY0382 to SJS)

Acknowledgements: People
.
The authors would like to especially recognize Dr. Patrick
Shea for his expertise and help with this work.
We thank Mike Huey, Wes Throop, Robert Beckley, Patricia
Skyler, and Erik Lamb for their support in the field.

Lodgepole Pine Site
Ponderosa Pine Site
5 m 10 m 30 m 5 m 10 m 30 m
Mean Bias (sm -3 ) 0.10 0.02 0.00 0.03 0.01 0.00
Mean Error (sm -3 ) 0.14 0.05 0.01 0.05 0.01 0.01
Fractional Bias (%) 17 10 -16 15 21 47
Fractional Error (%) 35 33 52 39 38 69
Fa 2 (%) 83 90 65 87 85 53
Results: Time Averaged Concentrations

• To determine if SF 6 is a suitable surrogate
pheromone
– By correlating SF 6
concentrations to I. pini trap
catch
– But first: Evaluate flight behavior of I. pini
• Determine peak flight
Objective: Evaluation of
SF 6 as a surrogate
pheromone