evaluation of several wrf/nmm- cmaq vertical coupling configurations pius lee, jeff mcqueen, marina...

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