VISTAS Grid Resolution Sensitivity
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Transcript of VISTAS Grid Resolution Sensitivity
VISTAS Grid Resolution SensitivityRalph Morris, Bonyoung Koo and Steven Lau
ENVIRON International Corporation
Gail Tonnesen, Zion Wang, Chao-Jung ChienUniversity of California at Riverside
T.W. Tesche and Dennis McNallyAlpine Geophysics
National RPO Modeling Meeting
Denver, Colorado
May 24-25, 2004
Grid Resolution Sensitivity• Three VISTAS Phase I Episodes
– January 2002– July 1999– July 2001
• MM5 PX_ACM(2)• 36 km national RPO grid and 12 km
Southeast US VISTAS Grid• Examine Model Performance in VISTAS
Southeast US Domain
IMPROVE SO4 Fractional Bias and ErrorCMAQ 36 km and 12 km & CB4 and SAPRC99
SO4 Mean Fractional Bias
-40.0
-35.0
-30.0
-25.0
-20.0
-15.0
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
Jan '0
2 36k
m
Jan '0
2 12k
m
Jul '
99 36
km
Jul '
99 12
km
Jul '
01 36
km
Jul '
01 12
km
Mea
n Fra
ctio
nal
Bia
s
Base CaseSAPRC99
SO4 Mean Fractional Error
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
Jan '0
2 36k
m
Jan '0
2 12k
m
Jul '
99 36
km
Jul '
99 12
km
Jul '
01 36
km
Jul '
01 12
km
Mea
n Fra
ctio
nal
Err
or
Base CaseSAPRC99
IMPROVE NO3 Fractional Bias and ErrorCMAQ 36 km and 12 km & CB4 and SAPRC99
NO3 Mean Fractional Bias
-150.0
-125.0
-100.0
-75.0
-50.0
-25.0
0.0
25.0
50.0
Mea
n Fra
ctio
nal
Bia
s
Base CaseSAPRC99
NO3 Mean Fractional Error
0.0
25.0
50.0
75.0
100.0
125.0
150.0
Jan '0
2 36k
m
Jan '0
2 12k
m
Jul '
99 36
km
Jul '
99 12
km
Jul '
01 36
km
Jul '
01 12
km
Mea
n Fra
ctio
nal
Err
or
Base CaseSAPRC99
IMPROVE OC Fractional Bias and ErrorCMAQ 36 km and 12 km & CB4 and SAPRC99
OC Mean Fractional Bias
-100.0
-90.0
-80.0
-70.0
-60.0
-50.0
-40.0
-30.0
-20.0
-10.0
0.0
10.0
Jan '0
2 36k
m
Jan '0
2 12k
m
Jul '
99 36
km
Jul '
99 12
km
Jul '
01 36
km
Jul '
01 12
km
Mea
n Fra
ctio
nal
Bia
s
Base CaseSAPRC99
OC Mean Fractional Error
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
110.0
Jan '0
2 36k
m
Jan '0
2 12k
m
Jul '
99 36
km
Jul '
99 12
km
Jul '
01 36
km
Jul '
01 12
km
Mea
n Fra
ctio
nal
Err
or
Base CaseSAPRC99
Ozone Performance July 1999 EpisodeCMAQ and CAMx at 36 km and 12 km (CB4)
Mean Normalized Bias in 1- Hr Ozone, (%).
-20.0
-15.0
-10.0
-5.0
0.0
5.0
10.0
15.0
10-J
ul
11-J
ul
12-J
ul
13-J
ul
14-J
ul
15-J
ul
16-J
ul
17-J
ul
18-J
ul
19-J
ul
20-J
ul
21-J
ul
Ave
rage
Mea
n N
orm
aliz
ed B
ias,
%
CMAQ 36 Km CMAQ 12 Km CAMx 36 km CAMx 12 km
CMAQ ozone performance degradation to under-estimation with finer grid
CAMx ozone performance similar at 36 km and 12 km
CAMx 36/12/4 km Performance for MRPO June 18 – August 13, 2001 Episode
CAMx Base E Mean Normalized Bias, (%).
-100.0
-50.0
0.0
50.0
100.0
150.0
200.0
250.0
300.0
Bia
s, %
36 Km Grid 12 Km Grid 4 Km Grid
Mean Normalized Bias
Degradation in most gas-phase species with higher resolution
Aerosol species stay same or improve
CAMx 36/12/4 km Performance for MRPO June 18 – August 13, 2001 Episode
CAMx Base E Mean Normalized Gross Error, (%).
0.0
50.0
100.0
150.0
200.0
250.0
300.0
1-Hr N
O2
1-Hr N
Ox
1-Hr S
O2
1-Hr O
3
8-Hr O
3 O
C ECSO4
NO3NH4
CMSoil
PM2.5
PM10
RCFM
Gro
ss E
rror
, %
36 Km Grid 12 Km Grid 4 Km Grid
Mean Normalized Gross Error
Conclusions: Grid Resolution Sensitivity• Effects of grid resolution on model performance is
mixed• Changes in precipitation patterns and magnitudes can
have large effect locally• Changes in transport patterns also can have big local
effect (e.g., Jim Boylan’s analysis of sulfate clouds)• 12 km grid technically superior for grid modeling than
36 km, but still does not resolve point sources and urban areas very well
• 12 km takes more CPU time than 36 km• VISTAS Phase II annual modeling will use both 36 and
12 km grids