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