The New SCIPUFF Air Dispersion Model, with Comparison against CALPUFF

© 2018 – Lakes Environmental Software
Jesse Thé, Ph.D.
DMUG
Apr/19/2018
Evaluation of
SCIPUFF versus
CALPUFF in Complex
Terrain

© Copyright 2018 – Lakes Environmental Software
2
Objectives
1. CALPUFF and SCIPUFF/SCICHEM resolve
the transport of pollutants with different
approaches
2. To simplify evaluations, only passive gases
were evaluated (SCICHEM without
chemistry)
3. Does SCIPUFF produces significant
different concentrations than CALPUFF?

3
SCIPUFF / SCICHEM CALPUFF
Outperforms AERMOD Outperforms AERMOD after 3km
Accurately models to 2000km Accurately models to 300km
Windfield calculations DO NOT
require the 1960’s radius of
interpolation
CALMET requires RMAX1, RMAX2,
R1, R2, and TERRAD. These
“factors” may work well for only a
portion of the modelling domain.
Handles dense gas dispersion Does not handle dense gas
Easier data input, similar to
AERMOD
Complex data input
Complete CMAQ photo-chemistry Empirical chemistry
Comparison

4
Evaluation of the Comprehensive Air Quality Model with Extensions (CAMx) Against
Three Classical Mesoscale Tracer Experiments
by Bret A. Anderson, Kirk Baker, Chris Emery
9th CMAS Conference, Chapel Hill, NC, October 11, 2010
SCIPUFF outperforms CALPUFF by a significant margin
0
0.5
1
1.5
2
2.5
CALPUFF SCIPUFF HYSPLIT FLEXPART CAMx
RANK
RANK
“SCIPUFF performed
best over 46 ADM
models”

5
CTEX3 Tracer LRT Model Evaluation
Higher values better

Jesse Thé, Ph.D.
DMUG
Apr/19/2018
2nd Order Closure

7
2nd Order Closure?
1. Turbulence
 What mixes pollutants in the atmosphere
 Not solved directly
 Gaussian Plume + Dispersion curves =
Simplest turbulence model
2. To represent mixing / dilution we must
model turbulence

8
2nd Order Closure?
1. Navier Stokes Equations ‐ NS
2. Reynolds Averaged NS (RANS)
 Mean and fluctuating components
3. Produces more unknowns than Equations
4. Turbulence Closure: Creating “approximate”
equations to solve the unknowns
5. > 200 Closure schemes!
uuu 

9
Momentum Conservation
gVP
Dt
VD
 


2
x
xxxx
z
x
y
x
x
x
g
z
V
y
V
x
V
x
P
z
V
V
y
V
V
x
V
V
t
V
 

































2
2
2
2
2
2
y
yyyy
z
y
y
y
x
y
g
z
V
y
V
x
V
y
P
z
V
V
y
V
V
x
V
V
t
V
 




































2
2
2
2
2
2
z
zzzz
z
z
y
z
x
z
g
z
V
y
V
x
V
z
P
z
V
V
y
V
V
x
V
V
t
V
 

































2
2
2
2
2
2

10
Momentum Conservation
gVP
Dt
VD
 


2
zji
j
i
ii
guu
x
V
xx
P
Dt
VD
 
















 ''

''
jiuu ''
uu ''
vu ''
wu
''
vv ''
wv
''
ww

11
Example of Closure
1st order ‐ Gradient on mean flow











i
j
eddyji
x
u
uu  ''
2nd order ‐ Variance of fields – velocity, etc.
u
u uuu 
Instantaneous = Mean + Fluctuating

12
Closure Types
Closure Approximation Applied
0.5 Order Bulk Method
1st Order
• Gradient Transport
• Mixing Length
CALPUFF, AERMOD
2nd Oder
Variances of Wind,
Temp, Concentration
SCIPUFF
Non‐Local Schemes Large Eddy Simulation LES Models

13
Puff vs. Plume
CALPUFF
AERMOD

14
SCIPUFF
Lagrangian transport of
Gaussian puffs
Concentration field
represented by
collection of 3-D puffs
Q
+
Puffs characterized by
3-moments of the puff
concentration
– 0th Mass
– 1st Centroid
– 2nd Spread
Puff concentration

Jesse Thé, Ph.D.
DMUG
Apr/19/2018
Case Studies

16
Project Parameters
 July 15‐19, 2015 (5 days)
 POINT Source – SO2 – 100g/s
 Met Grid: 1km
 Receptor Spacing: 1km

17
1700m to 3000m
Hayden, Colorado

18
SCICHEM ‐ Hayden, CO
SCICHEM with MEDOC
WRF 1‐km ‐ Max: 506 μg/m3
July 17, hour 23 at ‐1.0, ‐2.0
July 15 , hour 9 at 0.0, 0.0

19
CALPUFF ‐ Hayden, CO
July 18, hour 21 at 1.5, 5.5
CALPUFF with Prognostic Data
July 15, hour 21 at ‐5.5, 3.5

20
CALPUFF ‐ Hayden, CO
WRF 1‐km ‐ MMIF CALPUFF‐Ready
Max: 159 μg/m3 – July 18, hour 22 at ‐4.5, 7.5
By-passing CALMET

21
Comparisons ‐ Hayden, CO
SCICHEM Vs CALPUFF
Max 1-Hour SO2
Concentration
SCICHEM – 4-km WRF (MMIF MEDOC) 792 μg/m3
CALPUFF – 4-km WRF (3D.DAT) 296 μg/m3
CALPUFF - 1-km WRF (MMIF CALMET.DAT) 159 μg/m3

22
Comparisons ‐ Hayden, CO

23
SCICHEM vs CALPUFF (1‐km)
SCICHEM 1‐KM WRF
Max: 506 μg/m3
CALPUFF 1‐KM WRF
Max: 128 μg/m3
Hayden, Colorado

24
Hayden, Colorado
SCICHEM 4‐KM WRF
Max: 792 μg/m3
CALPUFF 4‐KM WRF
Max: 296 μg/m3

25
SCICHEM vs CALPUFF Wind Field
SCICHEM 4‐KM WRF CALPUFF 4‐KM WRF
Hayden, Colorado

26
Sea level to 1500m
Rio, Brazil

27
SCICHEM ‐ Rio, Brazil
SCICHEM with MEDOC
July 16, hour 9 at 0.0, 0.0
July 15, hour 9 at 0.0, 0.0

28
CALPUFF – Rio, Brazil
July 16, hour 2 at ‐2.5, ‐3.5
CALPUFF with Prognostic Data
July 16, hour 3 at ‐1.5, ‐4.5

29
CALPUFF – Rio, Brazil
WRF 1‐KM ‐ MMIF CALPUFF‐Ready
Max: 206 μg/m3 – July 17, hour 9 at ‐0.5, 0.5
By-passing CALMET

30
Comparisons – Rio, Brazil
SCICHEM Vs CALPUFF
Max 1-Hour SO2
Concentration
CALPUFF - 1-km WRF (MMIF CALMET.DAT) 206 μg/m3

31
Comparisons – Rio, Brazil

32
SCICHEM 1‐KM WRF
Max: 558 μg/m3
CALPUFF 1‐KM WRF
Max: 263 μg/m3
Rio, Brazil

33
Rio, Brazil
SCICHEM 4‐KM WRF
Max: 969 μg/m3
CALPUFF 4‐KM WRF
Max: 327 μg/m3

34
SCICHEM vs CALPUFF Wind Field
CALPUFF 4‐KM WRFSCICHEM 4‐KM WRF
Rio, Brazil

Jesse Thé, Ph.D.
DMUG
Apr/19/2018
Conclusions

36
Conclusions
1. CALPUFF and SCICHEM (SCIPUFF) generate
similar windfields when using WRF.
2. CALPUFF and SCIPUFF respond with
substantial concentration differences when
using WRF 4‐km and WRF 1‐km resolutions.
3. Higher resolution grids, in this case WRF 1‐km,
consistently produced smaller 1‐hour
maximum concentrations.

37
Future Research
1. Evaluation supports the Hypothesis that
SCIPUFF produces substantially different
results from CALPUFF for “non‐reacting”
pollutants.
2. Next step is to evaluate SCIPUFF against
CALPUFF at multiple sites over extended
periods.

38
Questions ?

39
uuu 
u
u
Instantaneous = Mean + Fluctuating
Turbulence

40
IHOP Experiment – Windfield
SCIPUFF
Observed
MM5
WRF

41
ETEX ‐ SCIPUFF
SCIPUFF performed
best over 46 ADM
models

42
1. Develop prognostic
equations for each of the
moments
2. Assume that puff centroid
is representative of the
whole puff
3. Splitting and merging of
puffs
SPLIT
MERGE
Boundary
SCIPUFF

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