understanding the usepa’s aermod modeling system for environmental managers
DESCRIPTION
Understanding the USEPA’s AERMOD Modeling System for Environmental Managers. Model Evaluation. Ashok Kumar University of Toledo [email protected]. Evaluation Studies on AERMOD. USEPA Evaluation using field studies No evaluation using ambient air monitoring network in an urban area. - PowerPoint PPT PresentationTRANSCRIPT
Air Pollution Research Group
Understanding the USEPA’s AERMOD Modeling System for
Environmental Managers
Ashok KumarUniversity of Toledo
Model Evaluation
Air Pollution Research Group
Evaluation Studies on AERMOD
USEPA Evaluation using field studies No evaluation using ambient air monitoring
network in an urban area
Air Pollution Research Group
Lucas County: Sources and Monitoring Stations
SOURCE AND MONITOR LOCATIONS FOR SO2
4608
4610
4612
4614
4616
4618
4620
286 288 290 292 294 296 298
EASTING (UTM) KM
NO
RT
HIN
G (
UT
M)
KM
MAIN SOURCES SUPERSTACKS MONITORING STATIONS
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Input Data Flow in AERMOD
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Data Requirements for Model Evaluation
Emission Inventory Properties of stacks and super stacks Meteorological data Receptor data Air monitoring data
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AERMET - Input
1. Meteorological Input Parameters – Multi-Level WS, WD, and Temperature, Opaque Cloud Cover, Ceiling Height, RH, Pressure, Surface Heat Flux, Friction Velocity, and Roughness Length, Delta-T , Solar Radiation, Upper Air Data
2. Data Formats - CD144, SCRAM, SAMPSON (surface data)
1. TD 3280 (surface data )
2. TD6201 (upper air data)
3. On-site (site specific data)
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AERMET - Output
Boundary Layer File sensible heat flux surface friction velocity convective velocity scale potential temp. gradient above
mixing height convectively-driven mixing height mechanically-driven mixing height Monin-Obukhov length surface roughness length Bowen ratio albedo
Profile File Measurement height WD, WS Temperature Standard Dev. of
Lateral WD Standard Dev. of
Vertical WS
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Atmospheric Stability
AERMOD uses Monin-Obukhov length as the stability parameter
You will need friction velocity u*and the flux of sensible heat H to compute L
L is defined to be negative in convective conditions and positive in stable
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AERMAP
Input data needs for AERMAP: DEM formatted terrain data User provided receptors and terrain Design of receptor grid: AERMAP accepts
either polar, cartesian or discrete receptors
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Pathways Used in AERMOD Input Runstream
Control Source Receptor Meteorology Output
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Statistical Evaluation Methods
Fractional Bias (FB)
Normalized Mean Square Error (NMSE)
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Statistical Evaluation Methods
Coefficient of Correlation (COR)
Factor of Two (Fa2)Fraction of data for which 0.5<Cp/Co<2
po cc
pooo CCCCr
))((
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Statistical Evaluation Methods
Confidence LimitsConfidence limits are the lower and upper boundaries / values of a confidence interval, that is, the values which define the range of a confidence interval. The upper and lower bounds of a 95% confidence interval are the 95% confidence limits.
Q-Q PlotsThe quantile-quantile (Q-Q) plot is a graphical technique for determining if two data sets come from populations with a common distribution.
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Results & Discussion
Model is evaluated in the following ways: Performance measures and confidence limits for3-hr average for SO2
Stable Condition Convective Condition
24-hr average for SO2
Plots of NMSE vs.FB Q-Q plots for 3-hr average for S02
Q-Q plots for 24-hr average for S02
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NMSE vs FB plots (3-hr average)
Plot of NMSE VS. FB (Main Street Station - Stable Case)
0
0.5
1
1.5
2
2.5
-1.5 -1 -0.5 0 0.5 1 1.5
FB
NM
SE
NMSE CURVE NMSE VERSUS FB
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NMSE vs. FB plots(3-hr average)
Plot of NMSE VS. FB (Main Street Station - Convective Case)
0
1
2
3
4
-1.5 -1 -0.5 0 0.5 1 1.5
FB
NM
SE
NMSE CURVE NMSE VERSUS FB
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NMSE vs. FB plots (3-hr average)
Plot of NMSE VS. FB (Collins Park Station - Stable Case)
0123456
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
FB
NM
SE
NMSE CURVE NMSE VERSUS FB
Air Pollution Research Group
NMSE vs. FB plots (3-hr average)
Plot of NMSE VS. FB (Collins Park Station - Convective Case)
0
1
2
3
4
-1.5 -1 -0.5 0 0.5 1 1.5
FB
NM
SE
NMSE CURVE NMSE VERSUS FB
Air Pollution Research Group
NMSE vs. FB plots (24-hr average)
Plot of NMSE VS. FB
0
0.5
1
1.5
2
2.5
-1.5 -1 -0.5 0 0.5 1 1.5
FB
NM
SE
NMSE CURVE NMSE VERSUS FB (Main Street)
NMSE VERSUS FB (Collins Park)
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Q-Q plots (3-hr average)
70 7080 8090 90
100 100
Q-Q plot for 3-hr average for Main Street Station - Stable Case
0
50
100
150
0.00 20.00 40.00 60.00 80.00 100.00 120.00
Observed Concentrations (μg/m3)
Pre
dic
ted
C
on
cen
trat
ion
s (μ
g/m
3)
Q-Q plot Reference line
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Q-Q plots (3-hr average)
Q-Q plot for 3-hr average for Main Street Station - Convective Case
0
50
100
150
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00
Observed Concentrations (μg/m3)
Pre
dic
ted
C
on
ce
ntr
ati
on
s
(μg
/m3
)
Q-Q plot Reference line
Air Pollution Research Group
Q-Q plots (3-hr average)
Q-Q plot for 3-hr average for Collins Park Station - Stable Case
02040
6080
0 10 20 30 40 50 60 70
Observed Concentrations (μg/m3)
Pre
dic
ted
C
on
ce
ntr
ati
on
s
(μg
/m3
)
Q-Q plot Reference line
Air Pollution Research Group
Q-Q plots (3-hr average)
Q-Q plots for 3-hr average for Collins Park Station - Convective Case
02040
6080
0 20 40 60 80
Observed Concentrations (μg/m3)
Pre
dic
ted
C
on
ce
ntr
ati
on
s
(μg
/m3
)
Q-Q plot Reference line
Air Pollution Research Group
Q-Q plots (3-hr average) Observed Concentrations
< 20µg/m3Q-Q plots for 3-hr average for Main Street Station - Stable Case
0
5
10
15
20
25
0.00 5.00 10.00 15.00 20.00 25.00
Observed Concentrations (µg/m3)
Pre
dic
ted
Co
ncen
trati
on
s(µ
g/m
3)
Air Pollution Research Group
Q-Q plots (3-hr average) Observed Concentrations
< 20µg/m3Q-Q plots for 3-hr average for Main Street Station - Convective
Case
0
5
10
15
20
25
0.00 5.00 10.00 15.00 20.00 25.00
Observed Concentrations (µg/m3)
Pre
dic
ted
Co
ncen
trati
on
s (
µg
/m3)
Air Pollution Research Group
Q-Q plots (3-hr average) Observed Concentrations
< 20µg/m3Q-Q plots for 3-hr average for Collins Park - Stable Case
0
5
10
15
20
25
0 5 10 15 20 25
Observed Concentrations (µg/m3)
Pre
dic
ted
Co
ncen
trati
on
s (
µg
/m3)
Air Pollution Research Group
Q-Q plots (3-hr average) Observed Concentrations
< 20µg/m3Q-Q plots for 3-hr average for Collins Park - Convective case
0
5
10
15
20
25
0 5 10 15 20 25
observed concentrations (µg/m3)
Pre
dic
ted
co
ncen
trati
on
s (
µg
/m3)
Air Pollution Research Group
Q-Q plots (24-hr average)
Q-Q plot for 24-hr average for Main Street Station
0
1020
30
40
5060
70
0 10 20 30 40 50 60 70
Observed Concentration (µg/m3)
Pre
dic
ted
Co
nc
en
tra
tio
n
(µg
/m3
)
Q-Q plot Reference line
Air Pollution Research Group
Q-Q plots (24-hr average)
Q-Q plot for 24-hr average for Collins Park Station
0
1020
30
40
5060
70
0 10 20 30 40 50 60 70
Observed Concentration (µg/m3)
Pre
dic
ted
Co
nc
en
tra
tio
n
(µg
/m3
)
Q-Q plot Reference line
Air Pollution Research Group
Confidence Limits (3-hr average)
The values of NMSE and FB were significantly different from zero in the stable case. COR was not significantly different from zero.
The values of NMSE, FB, and COR were not significantly different from zero for the convective case.
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Confidence Limits (24-hr average)
The values of NMSE and FB were significantly different from zero. COR, was not significantly different from zero.
Note: 24-hr data were not divided according to stability classes.