An Regional Enemble Kalman Filter Data Assimilation System Employing

GSI Observation Processing and Initial Tests for Rapid Refresh

Forecast Configurations

Kefeng Zhu, Yujie Pan, Xue Ming and Xuguang Wang

CAPS

Code development status• EnKFv1----we modified the global EnSRF code from Dr. Jeff

Whitaker of ESRL and linked this EnSRF package with the regional GSI for RR application.

• EnKFv2---- we merged regional EnKF with the latest global EnKF, by moving codes specific to regional EnKF into a unified version. And a new flag ‘iflagreg’ was added to control the regional analysis option. In this unified version, the variables updated during the regional EnKF assimilation were x-component wind (U), y-component wind (V), potential temperature (T), perturbation geopotential (PH, not used in the previous EnKFv1), water vapor mixing ratio (Q) and perturbation dry air mass in column (Mu).

• EnKFv3----instead of interpolating the U and V to the A grid during the EnKF analysis process, we keep the U and V in the original C grids

~13km Rapid Refresh(RR)

GSI

conventionalobservation

satelliteretreive windand radiance

radar windsobservation

3dvar

cloud analysis

surfaceMetar

NESDIS cloudtop products

NSSL 3D radarreflectivity

analyzed fields

3D latent heatrate

2D convectionsupression area

0-10m-20m

10m

RR-WRF-TDFI

WRF 12h forecast

1h forecast

GSI

OBS

GSI

OBS

GSI

OBS

GSI

OBS

BackgroudFields

12 hours forecast

12 hours forecast

12 hours forecast

12 hours forecast

12 hours forecastAnalysisFields

12-hours RR Hourly Assimilation Cycle

Diabatic integration

Full physics integration

MET

GSI

conventionalobservation

satelliteretreive windand radiance

3DVAR

0-10m-20m

10m

WRF-TDFI

~40km WRF 24h forecast

3h forecast

observationinnovations EnKF

analyzed fields

diabatic integration

full physics integration

00,12Z

Interpolateto ~13km

GSI cloudanalysis

~13kmWRF

Ref

YES

No

wrfout_d01*

wrfout_d02*

WPP

00,12Z

Point_stat:~40km RMSE

grid_stat:~13km

precipitation

Verification followed

EnSRF

EnSRF—RR

RUC

EnKF Test Domain207x207 grid points~40 km, 51 levelsThe 13 km RR-like forecast Domain532x532 grid points~13 km, 51 levelsCurrent RUC Domain as indicated

Domains

Experiment flowchart

ADPSFCADPSFC

SFCSHP

ADPSFC

280/180

281/181284/184

287/187

221

ADPUPA

SFCSHP282

ADPUPA220/120

Observation type used for verificationSurface:

Land--- 287,281,284 (U,V)187,181,184 (RH,T,PRMSL)

Sea---280,282 (U,V)180 (RH,T,PRMSL)

Up air: 220,221,223 (U,V)120 (RH,T,PRMSL)Quality mark: 2

PROFLR

223

Experiment Simple covariance

State-dependent Horizontal (km)

EnKFnofixA02L06

b=0 c=0.2 rcut=600

EnKFfixA02L06 b=0.2 c=0.2 rcut=600

EnKFfixA09L12 b=0.2 c=0.9 rcut=1200

GSI

Inflation factors and horizontal cutoff radius configuration test

Note: Here the EnKF comes from the 40 members 3-h forecast ensemble mean; GSI is a single deterministic forecast. The verification period are from 00 UTC May 8 ~ 06 UTC May 16, 2010. There are 66 samples collected for the observation type ADPSFC, SFCSHP, PROFLR, but 16 samples for the ADPUPA

Horizontal and vertical localization factor

1

2

1

1

(1 ) ,

1( ( ) ( ))

1

1( )( ( )

( ) ( ) (ln

( )

( /

)

) )

1

f T

f T f T

Nf T f f

ii

Nf T f f f f

i i

ob a dis at h v

cut

i

cut ob

t t r ptape

R P HK

HP H R HP H R

HP H H x H xN

r taper taper lncutt

P H x x

p

H H x

r

xN

' ( ) ( ( ) ( ))

( ( ))

a f f f fi i i

a f o f

x x x K H x H x

x x K y H x

where

Inflation algorithms• Simple covariance

• State-dependent covariance inflation

• Double inflation

' '1

1 (ln( ) / )

a a

a

sfc

x x

pb taper lncut

p

' '2

2 2

2 21

a a

f a

a

x x

c

taper(r)

1000 , 6sfcp hPa lncut

925ap hPa

700ap hPa

500ap hPa

300ap hPa

1 2

RH---ADPUPA

T---ADPUPA

V---ADPUPA

U---ADPUPA U---PROFLR

V---PROFLR

Experiment Simple covariance

State-dependent

Vertical Horizontal (km)

EnKFLn20VH b=0.2 c=0.9 lncut=2.0 rcut=1200*500/pob

EnKFLn12VOb b=0.2 c=0.9 lncut=1.2 Varies with ob type

EnKFLn11VObH b=0.2 c=0.9 lncut=1.1lncutps=1.5

Varies with ob type and height

GSI  

Vertical and horizontal cutoff radius setting test

Note: Here the EnKF comes from the 40 members 3-h forecast ensemble mean; GSI is a single deterministic forecast. The verification period are from 00 UTC May 8 ~ 06 UTC May 16, 2010. There are 66 samples collected for the observation type ADPSFC, SFCSHP, PROFLR, but 16 samples for the ADPUPA

RH---ADPUPA

T---ADPUPA

V---ADPUPA

U---ADPUPA U---PROFLR

V---PROFLR

Casename DFI setting Vertical Horizontal (km)

EnKFdfi20m40s Backward 20mForward 10mdfi_cutoff_seconds=3600stime_step_dfi=40s

lncut=1.1lncutps=1.5

Varies with ob type and

height

EnKFdfi40m60s Backward 40mForward 20mdfi_cutoff_seconds=3600stime_step_dfi=60s

lncut=1.2lncutps=1.2

Varies with ob type

EnKFdfi40m40s Backward 40mForward 20mdfi_cutoff_seconds=2800stime_step_dfi=40s

lncut=1.2lncutps=2.0

Varies with ob type

GSI Backward 20mForward 10mdfi_cutoff_seconds=3600stime_step_dfi=40s

DFI setting test

EnKFdfi20m40s3600s/GSI/GFS EnKFdfi40m60s3600s

EnKFdfi40m40s2800s

1 1

1

*

nynxs

i j

pN

nx ny t

RH---ADPUPA

T---ADPUPA

V---ADPUPA

U---ADPUPA

U---PROFLR

V---PROFLR

land sea

Surface verification: The plots above are the average forecasts innovation of single forecast from ensemble mean analyses for the time period from 00UTC May 8 to 03 UTC May 16, 2010. The cycle interval is 3 hours. Totally, there are 66 samples for this statistic.

Up air verification: since the observation of ADPUPA are only available at 00, 12 Z. Therefore, for the vertical profile followed, we average the 12 hour forecasts innovation from 00, 12Z. There are totally 17 samples.

Longer hour single forecast from ensemble mean analyses

Temperature at 2m-Land Temperature at 2m-Sea

RH at 2m-Land RH at 2m-Sea

U at 10m-Land U at 10m-Sea

V at 10m-Land V at 10m-Sea

3h 6h 9h

12h 15h 18h

RH

3h 6h 9h

12h 15h 18h

Tmperature

3h 6h 9h

12h 15h 18h

UGRD---ADPUPA

3h 6h 9h

12h 15h 18h

VGRD---ADPUPA

3h 6h 9h

12h 15h 18h

UGRD---PROFLR

3h 6h 9h

12h 15h 18h

VGRD---PROFLR

MET

GSI

conventionalobservation

satelliteretreive windand radiance

3DVAR

0-10m-20m

10m

WRF-TDFI

~40km WRF 24h forecast

3h forecast

observationinnovations EnKF

analyzed fields

diabatic integration

full physics integration

00,12Z

Interpolateto ~13km

GSI cloudanalysis

~13kmWRF

Ref

YES

No

wrfout_d01*

wrfout_d02*

WPP

00,12Z

Point_stat:~40km RMSE

grid_stat:~13km

precipitation13 km Verification followedAgainst Stage IV---GSS(ETS)

GSS (ETS) scores

00~12 UTC May 10,2010

Stage IV

00~12 UTC May 11,2010

00~12 UTC May 13,2010

GSI based forecast EnKF based forecast