Evaluation of several WRF/NMM-CMAQ vertical coupling configurations
Pius Lee, Jeff McQueen, Marina Tsildulko, Geoff DiMegoSarah Lu and Bert Katz
NOAA/NCEP Environmental Modeling Center
Rohit Mathur, Hsin-Mu Lin, Daiwen Kang, Tanya Otte, Jon Pleim, George Pouliot, David Wong, Jeff Young, and
Ken Schere
U.S. EPA/ORD/ASMD and NOAA/OAR/ARL
WRF/NMM Hybrid Coordinate
ground
Pressure domain
Sigma domain
η1= 1; η2= 0
η1= 1; η2= 1
PT
HYBRID
PDT+PT
η1= 0; η2= 0
Upper-levels Pressure
Lower-levels σ-p
Lin et al, Poster Session 3.1
WRF/NMM
T2T1 PPDPDP
T
T2
TT1 PD
PP,
PD
)P(PDP
2
)(1)(1x 21
3
3x
zJ
2313
223113h ΔxΔx
JΔxJΔxJ
ρg
2PDJ1
ρg
2PDJ T
2
’s limited to 0-1
Jacobian across the -p interface
Lin et al, Poster Session 3.1
Remarks on the hybrid layer cases • (22L) 22 layers: Choose model layers
aligned close to those used in the current National Air Quality Forecast System (AQFS). 14 lowest layers spanned ~ 2 km
• *(29L) 29 layers: Finer resolution than (a) in lowest 500m; top of PBL; and near tropopause.
• (40L) 40 layers: As fine as the met model for lowest 3.5 km.
*29L result rather similar to that of 22L
Hybrid (a) 22L, (b) 29L, and (c) 40L
O3 episode (h max) Aug 3rd, 2006
22L-40L
40L reduced low bias for regions near Bakersfield
40L reduced highbias for regionsnear mid Long Island
Spatial verification for 22L
Spatial verification for 40L
Spatial verification for 40L
Cross sectionon Central Valley, CA
Cross sectionon Mid Long Island, NY
S
S
N
N
W
W
E
E
Bakersfield
1 pm Local
PBL and Kz descriptionswith less interoplation error
O3
S
S
N
N
W
W E
E
Bakersfield1 am local
O3
Resolves inversion better, retains more residual O3
NOy
S
S
N
N
W
W
E
E
Bakersfield 1 pm Local
Industrial plumefrom south.
S
S
N
N W
W
E
E
Bakersfield1 am local
NOy
Lower diffusivityResulted in relativelyun-dispersed plumeheading eastward
Formaldehyde
S
S
N
N W
W
E
E
Bakersfield 1 pm Local
A more concentratedplume of VOC and biogenicproduct coming fromSouthwest
S
S
N
N W
W
E
E
Bakersfield1 am local
Formaldehyde
Better descriptionof residual andsurface layers
CO
S
S
N
N W
W E
E
Bakersfield 1 pm Local
S
S
N
N W
W
E
E
Bakersfield1 am local
CO
Better descriptionof inversion, increasedsurface level concentrations
O3
S
S
N
N W
W E
E
Mid Long Island4 pm local time
Increased high biasfor an offshorepoint to the southof Long Island
Decrease high biasfor New York City
S
S
N
N
W
W
E
E
O3
Mid Long Island4 am local time
Stronger inversionresulted in higherconcentration in residual layer
S
S
N
N W
W
E
E
Mid Long Island4 pm local time
NOy
Better description of PBLalso better descriptionof sea breeze return flow
S
S
N
N
W
W E
E
Mid Long Island
4 am local time
NOy
Species such as PANwill contribute toelevated surface O3upon sunrise
S
S
N
N
W
W
E
E
Mid Long Island4 pm local time
Formaldehyde
Reduction of high biasnear New York Cityfor VOC and biogenicphotochemical products
S
S
N
N
W
W E
E
Mid Long Island4 am local time
Formaldehyde
Maintains a less dispersedplume of sea breeze return flow
Summary
Three resolutions of a lower-levels σ-p terrain following and upper-levels pressure hybrid vertical co-ordinate systems have been tested: (a) 22L, (b) 29L, and ( c) 40L
40L is superior in two challenging localities: (1) Central Valley, CA:
Perennial inversion; andSubsidence due to orographic and channel flows
(2) Long Island, NY:Surrounding complex terrain and land-sea breezes
Future work: Derivation of an Optimal vertical structure
•σ
22L-29L
29L-40L
Spatial verification for 29L
Definition based on a scatter plot
a b
c d
Definitions of measures
•
Categorical Statistics over 8/2-4, 2006
FC B FAR POD CSI a b c d
22L
98.48 2.04 54.39 18.39 8.76 5.3 2.7 1075.7 11.3
29L
98.36 1.66 77.78 10.86 7.96 6.7 2.7 1074.3 11.3
40L
98.27 2.08 81.74 11.94 8.18 8 3 1073 11
S
S N
N
W
W E
E
Mid Long Island4 pm local time
Surface SOx
S
S N
N W
W
E
E
Mid Long Island4 am local time
Surface SOx
S
S N
N W
W E
E
Mid Long Island
4 pm local time
Surface CO
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