Transcript Effect of temporal averaging of vertical eddy diffusivity on the forecast accuracy of surface O3 Pius Lee, Youhua Tang, Jeff McQueen, Ho-Chun.

Effect of temporal averaging of vertical eddy
diffusivity on the forecast accuracy of surface O3
Pius Lee, Youhua Tang, Jeff McQueen, Ho-Chun Huang,
Marina Tsildulko, Geoff DiMego, Sarah Lu and Geoff DiMego
NOAA/NCEP
Environmental Modeling Center
Ivanka Stajner, Ken Carey, and Paula Davidson
Office and Science and Technology, NWS
Jon Pleim, Rohit Mathur, Hsin-Mu Lin, Daiwen Kang,
George Pouliot, Jeff Young, Shaocai Yu, Daniel Tong, Tianfang Chai
U.S. EPA
Elevated O3 episode Aug 3rd, 2006
Sensitivity cases
Case name
Description
Base
Real-time NCEP production
CMAQ-4.5 RADM PBL scheme
NAM Kh
Directly read in NAM
instantaneous Kh to plug in
CMAQ’s vertical diffusion
NAM hrly Kh
As above but uses hourly
averaged Kh ( scheme used is
analogous to precip buckets
emptied at full hours )
Kz (m2 s-1) over Table Mountain, CA
on August 2nd-3rd, 2006 @2285m
Ozonesonde launched
at 20:52UTC
18UTC
20UTC
21UTC
00UTC
TKE-PBL
Inferred PBLH
From ozonesonde
Temporal smoothing
used in this study
postponed vigorous
Kz (m2 s-1) over Boulder, CO
on August 2nd-3rd 2006 @1745m
TKE-PBL
Inferred PBLH
From ozonesonde
19UTC
20UTC
23UTC
02UTC
Ozonesonde launched
at 19:28UTC
Kz (m2 s-1) over Huntsville, AL
on August 2nd, 2006 @196m
TKE-PBL
Inferred PBLH
From ozonesonde
15UTC
17UTC
21UTC
18UTC
Ozonesonde launched
at 17:36UTC
Kh (m2 s-1) over Beltsville, MD
on August 2nd, 2006 @24m
TKE-PBL
Inferred PBLH
From ozonesonde
19UTC
15UTC
23UTC
20UTC
Ozonesonde launched
at 19:18UTC
Time-height on NO2 at Table Mountain on Aug 2nd-3rd, 2006
NAM Kh
NAM hrly Kh
Base
There is considerable amount
of NO2 at night. (Table Mount is
roughly 80 km to the North east
of L.A. at elevation of 2285 m.)
Surface O3 diff cases: Kh - hrly_Kh on Aug 2nd-3rd, 2006
18UTC, 2nd
21UTC, 2nd
02UTC, 3rd
00UTC, 3rd
Very minor difference; if any is due to delayed mixing
Time-height on O3 at Table Mountain on Aug 2nd-3rd, 2006
NAM Kh
Base
At 2285 m
foggy near
ground
7000
NAM hrly Kh
Altitude (m)
6000
5000
Observed O3
Base O3
NAM Kh O3
NAM h-avg Kh O3
Observed RH
Predicted RH
4000
3000
0
20
40
60
80
O3 (ppb) or RH (%)
100
Inferred PBLH
From ozonesonde
120
140
Time-height on O3 at Boulder on Aug 2nd-3rd, 2006
NAM Kh
Base
Inferred PBLH
From ozonesonde
7000
NAM hrly Kh
Altitude (m)
6000
5000
4000
Observed O3
Base O3
NAM Kh O3
NAM h-avg Kh O3
Observed RH
Predicted RH
3000
2000
0
20
40
60
80
O3 (ppb) or RH (%)
100
120
140
Time-height on O3 at Huntsville on Aug 2nd-3rd, 2006
NAM Kh
Base
7000
6000
Altitude (m)
5000
NAM hrly Kh
Inferred PBLH
From ozonesonde
4000
3000
Observed O3
Base O3
NAM Kh O3
NAM h-avg Kh O3
Observed RH
Predicted RH
2000
1000
0
20
40
60
80
O3 (ppb) or RH (%)
100
120
140
Time-height on O3 at Beltsville on Aug 2nd-3rd, 2006
NAM Kh
Base
7000
6000
NAM hrly Kh
Altitude (m)
5000
Rather large
overshot of
PBLH
4000
3000
Observed O3
Base O3
NAM Kh O3
NAM h-avg Kh O3
Observed RH
Predicted RH
2000
1000
0
20
40
60
80
O3 (ppb) or RH (%)
100
120
Inferred PBLH
From ozonesonde
140
Summary
•
Direct use of NAM Kh has been attempted by:
1.
Use of instantaneous Kh at hourly data exchange from NAM
2.
Use hourly averaged Kh from NAM
•
These two approaches both showed better
agreement in reflecting atmospheric column where
turbulent mixing actually takes place when looking
at selected sites during the studies period of
August 2nd, 2006.
There is not much impact on daily maximum
surface O3 concentration, as Kh temporal averaging
tends to delay the peak occurrence by some 10’s
minutes but does not alter the hourly or 8 h daily
max.
•
Backups
Correlation of daily 8h max O3 with AIRNOW obs (7/30-8/4, 2008)
0.9
0.9
0.8
0.8
0.7
0.7
0.6
0.6
0.5
0.5
0.4
0.4
0.3
0.2
0.930-Jul
PC
31-Jul
0.8
0.7
0.6
0.5
0.3
1-Aug
2_Aug
3-Aug
Base
NAM Kh
NAM hrly Kh
0.2
0.930-Jul
RM
31-Jul
2_Aug
3-Aug
0.2
0.9
30-Jul
4-Aug
0.8
0.7
0.7
0.6
0.6
0.5
0.5
0.4
0.4
0.2
30-Jul
LM
31-Jul
1-Aug
2_Aug
3-Aug
2_Aug
3-Aug
4-Aug
1-Aug
2_Aug
3-Aug
4-Aug
1-Aug
2_Aug
3-Aug
4-Aug
0.5
0.8
0.3
1-Aug
0.6
0.3
1-Aug
31-Jul
0.7
0.4
0.4
0.3
0.2
0.9
30-Jul
4-Aug
0.8
UM
SE
31-Jul
0.3
NE
0.2
4-Aug 30-Jul
31-Jul
RSME of daily 8h max O3 with AIRNOW obs (7/30-8/4, 2008)
20
20
18
18
PC
16
16
14
14
12
12
10
10
8
8
20
30-Jul
18
31-Jul
1-Aug
2_Aug
3-Aug
6
2230-Jul
4-Aug
UM
31-Jul
1-Aug
2_Aug
3-Aug
4-Aug
1-Aug
2_Aug
3-Aug
4-Aug
1-Aug
2_Aug
3-Aug
4-Aug
20
RM
18
16
16
14
14
12
12
10
8
2030-Jul
18
10
31-Jul
1-Aug
LM
16
Base
8
22
2_Aug
3-Aug
4-Aug 30-Jul
NAM Kh
20
NAM hrly Kh 1816
31-Jul
14
14
12
12
10
10
8
30-Jul
SE
8
31-Jul
1-Aug
2_Aug
3-Aug
6
4-Aug 30-Jul
NE
31-Jul
PBL-Height verification across CONUS between July20-27, 2006
12 hr PBL verification
from launcher runs;
Valid 00z