Development of WRF-CMAQ Development of WRF-CMAQ Interface Processor (WCIP)Interface Processor (WCIP)

Seung-Bum Kim and Daewon W. ByunSeung-Bum Kim and Daewon W. ByunUniversity of HoustonUniversity of Houston

Air Quality Modeling and Monitoring CenterAir Quality Modeling and Monitoring Center

Development of WCIPBackground: NCAR/NOAA/Air Force is Developing

Weather Research and Forecasting (WRF) model to replace MM5 & NCEP Eta

Goal: Build consistent on/off-line WRF-chem model

Objectives:1) Demonstrate that CMAQ’s Fully-Compressible

Governing Set of Equations (FCGSEs) is Dynamically Consistent with WRF Eulerian Dynamic Cores:Mass (EM), Height (EH)

2) Provide algorithms for the WCIP implementation3) Mass conservation test of MM5, WRF-EH, WRF-

EM with CMAQ

CMAQ FCGSEs and WRF Dynamic Cores (1)

zszs

zzs

szs Jf

s

vJ

m

Jm

t

JVτ

VV

VV

3

32 ˆ

ˆ)(

)(

ssss

ss Js

p

z

s

g

mJp

mJ F̂

Horizontal Momentum Equation

Vertical Momentum Equation(Jsw)

tm2s

JswVz

m

(Jsw ˆ v 3 )

s

Jsm

p

ss

sz

Js F3

wQ

jiV 21 vvz horizontal wind vector on the reference earth-tangential Cartesian coordinates

zs mvv VjiV 21 ˆ ˆˆ ˆ v 3 ds

dts

t Vz zs w

s

z

Contra-variant wind components used in CMAQ

CMAQ’s FCGSEs and WRF Dynamic Cores (2)

Conservation Equations

Diagnostic Equations

(Js )

t m2s

Jsˆ V s

m2

(Jsˆ v 3 )

sJsQAir Density

Entropy Density

QJs

vJ

m

Jm

t

Js

ssss

s

)ˆ(ˆ)( 3

22 V

Pollutants (i Js )

tm2s

iJsˆ V s

m2

( i Jsˆ v 3 )

sJsQ i

)ln()ln(oo

doo

vd RT

TC

Entropy Density

Ideal Gas Law

Pressure

o

do p

Rpp

WRF Eulerian Mass (EM) Dynamic Core (1)

Vertical Coordinate: terrain following, time dependent hydrostatic pressure ()

Vertical momentum Eq.

Wind components

t

ts gJ s /

1vU 2vV 3vW 3v̂

)()( 2 w

m

wm

t

w z

V0

pg

ln

WRF Eulerian Mass (EM) Dynamic Core (2)

Conservation Equations

/2 Qm

mt

zs

V

QJm

mt s

zs

)(2 V

/)()( 2

iQ

q

m

qm

t

q iizi

V

WRF Eulerian Height (EH) Dynamic Core

),(

),(

yxhH

yxhz

s

s

),( yxhHJ ss

WCIP Met. Algorithms for EM CoreMass-Jacobian weighted Contravariant wind components

Comparison of WRF- W with omega-equation needed

zmgm

J

m

JVVV

ˆˆ22 gmm

J22

)at top 0 bottom,at 1sfor (1

)at top 1 bottom,at 0sfor (ˆ 3

s

sx

WCIP Met. Algorithms for EH Core

)()(ˆ

2 zs

m

hH

m

JVV

zwhm

tv

)ˆ(ˆ3 V

3

2

3

2ˆ

)(ˆ v

m

hHv

m

Js

Mass conservation test of MM5, WRF-EH, and WRF-EM with CMAQ

Purpose:Purpose:

1)1) To quantify the mass consistency of To quantify the mass consistency of each modeleach model

2)2) To find out possible problems in on/off-To find out possible problems in on/off-line WRF-chem modeling line WRF-chem modeling

Experimental DesignExperimental DesignIntegrationIntegration 08/26/00UTC-08/27/00UTC, 2000 (24hr)08/26/00UTC-08/27/00UTC, 2000 (24hr)

Grid sizeGrid size 4km4km

Time stepTime step 10 sec10 sec

IC/BCIC/BC Eta AWIP analysis dataEta AWIP analysis data

ModelModel MM5 v3.5MM5 v3.5 WRF mass WRF mass ver1.2.1ver1.2.1

WRF height WRF height ver1.2.1ver1.2.1

Horizontal gridHorizontal grid 161X146161X146 161X146161X146 161X146161X146

Vertical grid Vertical grid 4343 4343 4242

Physics (the same physics options are selected)Physics (the same physics options are selected)

MicrophysicsMicrophysics Simple iceSimple ice NCEP simple iceNCEP simple ice NCEP simple iceNCEP simple ice

Longwave rad.Longwave rad. RRTMRRTM RRTMRRTM RRTMRRTM

Shortwave rad.Shortwave rad. Dudhia(1989)Dudhia(1989) Dudhia(1989)Dudhia(1989) Dudhia(1989)Dudhia(1989)

Surface-layerSurface-layer MOSMOS MOSMOS MOSMOS

Land-surface Land-surface OSU-LSMOSU-LSM OSU-LSMOSU-LSM OSU-LSMOSU-LSM

Boundary-layerBoundary-layer MRFMRF MRFMRF MRFMRF

CumulusCumulus NoneNone NoneNone NoneNone

WCIP START

get env. variables

dyn_opt get_wrf_em

get_wrf_eh1

2

END

WCIP (WRF-CMAQ Interface Processor)

goto MCIPGRID_OUT

MET3DSUP

WCIP START

get env. variables

dyn_opt get_wrf_em

get_wrf_eh1

2

END

WCIP (WRF-CMAQ Interface Processor)

goto MCIPGRID_OUT

MET3DSUP

Major functions of current WCIPMajor functions of current WCIP Read WRF data Reconcile coordinate Horizontal interpolation Compute Jacobian, entropy, density, etc. Current WRF does not provide enough PBL parameters needed in CMAQ. We had to use PBL diagnostic routine built in MCIP in this implementation

Treatment of missing met. variables in WCIPTreatment of missing met. variables in WCIP

surface roughness, albedo, emissivity, surface surface roughness, albedo, emissivity, surface moisture availability moisture availability

use MCIP2 valuesuse MCIP2 values latlon and map scale factor on dot gridslatlon and map scale factor on dot grids interpolation using those on cross gridsinterpolation using those on cross grids Pressure, density at full layersPressure, density at full layers diagnosed by using ideal gas law diagnosed by using ideal gas law

To avoid errors from interpolation or approximation, we better ask WRF group to make special output procedure for AQ modeling group

Jacobian of WRF EMJacobian of WRF EM06 UTC06 UTC 18 UTC18 UTC

Jacobian-weighted density varies with time,Jacobian-weighted density varies with time,

but it is constant vertically in WRF EM coordinatebut it is constant vertically in WRF EM coordinate

Jacobians of MM5 and WRF EHJacobians of MM5 and WRF EH

WRF heightMM5

Difference of Initialization processDifference of Initialization process Although we tried to make comparable Although we tried to make comparable

MM5 and WRF outputs in this MM5 and WRF outputs in this experiment, we have found MM5 experiment, we have found MM5 initialization routine provides organized initialization routine provides organized vertical wind field initially, but, for vertical wind field initially, but, for some reason, WRF SI routine does not some reason, WRF SI routine does not generate any initial vertical motion.generate any initial vertical motion.

However, initial horizontal motion field However, initial horizontal motion field was quite similar. was quite similar.

Vertical Velocity at surface layer Vertical Velocity at surface layer 2000/08/26/00UTC (Initial Time)2000/08/26/00UTC (Initial Time)

MM5

zero field

WRF mass

Benefit of WRF EMBenefit of WRF EM The benefit of WRF EM over WRF EH is that The benefit of WRF EM over WRF EH is that

the tendency of Jacobian-weighted density the tendency of Jacobian-weighted density shown in coordinate transform becomes the shown in coordinate transform becomes the tendency of surface pressure in WRF EM, tendency of surface pressure in WRF EM,

so that the vertical wind can be determined so that the vertical wind can be determined based on the divergence in the layer and the based on the divergence in the layer and the tendency of surface pressure term.tendency of surface pressure term.

This can be still applied to non-hydrostatic This can be still applied to non-hydrostatic fully compressible atmosphere as long as we fully compressible atmosphere as long as we rely on hydrostatic pressure as coordinate.rely on hydrostatic pressure as coordinate.

Contravariant Vertical Velocity Contravariant Vertical Velocity in WRF EM dynamical corein WRF EM dynamical core

0 1

22

0

ˆ( )J Vm d

t t m

22

ˆ' ( )

T

T

T

Vm d

m t

The tendency eq. for the surface hydrostatic pressure from continuity eq. in the ideal case using the boundary conditions at top and bottom :

Since eta is a material coordinate, the air density does not explicitly appear in the continuity equation. Therefore, it can be used to estimate the contravariant vertical velocity component by integrating the wind divergence term either from the bottom to a level eta or from the top to eta:

0

0

202

ˆ' ( )

Vm d

m t

(downward integration)

(upward integration)

WHAT_JD (70,20) 00/08/26/18UTC

kg/(m*s)

-0.4 -0.2 0.0 0.2 0.4 0.6

Ver

tical

Gri

d N

umbe

r

0

5

10

15

20

25

30

35

40

eta-dotOmega Eq.

WHAT_JD (46,15) 00/08/26/18UTC

kg/(m*s)

-0.4 -0.2 0.0 0.2 0.4 0.6

Ver

tical

Gri

d N

umbe

r

0

5

10

15

20

25

30

35

40

eta-dotOmega Eq.

Difference of vertical momentum Difference of vertical momentum component in generalized coordinatecomponent in generalized coordinate

WHAT_JD (46,46) 00/08/26/18UTC

kg/(m*s)

-0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15

Ver

tical

Gri

d N

umbe

r

0

5

10

15

20

25

30

35

40

eta-dotOmega Eq.

Gravity wave

pattern

WRF may need

normal mode

initialization,

because

this pattern

is not realistic !!!

Mass conservative temporal Mass conservative temporal interpolation method (I)interpolation method (I)

1(1 ) n nt t t

1( ) (1 )( ) ( )s s n s nJ J J 1( ) (1 )( ) ( )s s n s nJ J J

The Jacobian and density at a time

1( ) (1 )( ) ( )s s ss s n s nJ V J V J V

Wind components multiplied with Jacobian-weightdensity are interpolated linearly,

3 3 31( ) (1 )( ) ( )s s n s nJ v J v J v

( )sJ

t

Mass conservative temporal Mass conservative temporal interpolation method (II)interpolation method (II)

ˆ( )ˆ( )( )

s ss

s

J VV

J

Finally, interpolated wind components are derived with:

33 ˆ( )

ˆ( )( )

s

s

J vv

J

Vertical velocity multiplied with Vertical velocity multiplied with Jacobian-weighted densityJacobian-weighted density

2000/08/26/06UTC2000/08/26/06UTC

MM5 WRF mass WRF height

PBL heightPBL height

MM5

WRF mass

WRF height

Vertical Velocity at Vertical Velocity at surface layer surface layer

2000/08/26/20UTC (14LST)2000/08/26/20UTC (14LST)

MM5 WRF mass

(31,50)(31,50)

Normalized IC1_BC1 concentrationNormalized IC1_BC1 concentrationVertical velocity (in WRF mass)Vertical velocity (in WRF mass)

Normalized IC1_BC1 (2000/08/26)

TIME (hr)

0 3 6 9 12 15 18 21 24

ppm

V

0.90

0.92

0.94

0.96

0.98

1.00

1.02

eta-dotomega equation

RED: w-component on mass coordinate directly from WRF massBLACK: vertical velocity on mass coordinate in WCIP using omega equation

Hourly WRF EM data have mass consistency !!!!Hourly WRF EM data have mass consistency !!!!

Normalized IC1_BC1 concentrationNormalized IC1_BC1 concentrationMM5, WRF mass, WRF heightMM5, WRF mass, WRF height

(No Collapsing)(No Collapsing)

Normalized IC1_BC1 (2000/08/26)

TIME (hr)

0 3 6 9 12 15 18 21 24

CO

NC

EN

TR

AT

ION

(p

pm

V)

0.88

0.90

0.92

0.94

0.96

0.98

1.00

1.02

MM5WRF massWRF height

In spite of existence of gravity wave mode, WRF EM shows massIn spite of existence of gravity wave mode, WRF EM shows mass

consistency characteristics as good as MM5 or a little bit better. consistency characteristics as good as MM5 or a little bit better.

Normalized IC1_BC1 concentrationNormalized IC1_BC1 concentrationEffects of CollapsingEffects of Collapsing

MM5

0 3 6 9 12 15 18 21 24

pp

mV

0.820.840.860.880.900.920.940.960.981.001.02

FULL (43)23 layers

WRF height

TIME (hr)

0 3 6 9 12 15 18 21 24

pp

mV

0.820.840.860.880.900.920.940.960.981.001.02

FULL (42)23 layers

WRF mass

0 3 6 9 12 15 18 21 24

pp

mV

0.800.820.840.860.880.900.920.940.960.981.001.02

FULL (43)23 layers

Normalized IC1_BC1 (2000/08/26)

Collapsing damages Collapsing damages

mass conservation mass conservation

characteristics characteristics

significantly!!!significantly!!!

Are high frequency met. data always better?Are high frequency met. data always better?Time Resolution IssueTime Resolution Issue

TIME (HH/MM)

18/00 18/10 18/20 18/30 18/40 18/50 19/00

pp

mV

0.992

0.994

0.996

0.998

1.000

1.002

10sec met. data with dt = 10 sec1hr met. data with dt = 10 sec

WRF mass

This result shows us that high-frequcy met. data might be worseThis result shows us that high-frequcy met. data might be worse

for mass conservation for mass conservation need the consistent numerical need the consistent numerical

transport algorithm between meteorological and chemistry-transporttransport algorithm between meteorological and chemistry-transport

modelmodel

Summary and ConclusionsSummary and Conclusions On the way we develop consistent on/off-line WRF-On the way we develop consistent on/off-line WRF-

chem model,chem model,

1) Reliable WCIP has been developed.1) Reliable WCIP has been developed.

2) We need to communicate with WRF group on the 2) We need to communicate with WRF group on the following issues:following issues:

Although many met. parameters needed in the CMAQ Although many met. parameters needed in the CMAQ are calculated in the WRF, they are not included in are calculated in the WRF, they are not included in standard output of WRF presently.standard output of WRF presently.

According to the mass conservation test, we need build According to the mass conservation test, we need build consistent transport numerical algorithms both in WRF consistent transport numerical algorithms both in WRF and CMAQand CMAQ