COSMO-SREPS Priority Project
C. MarsigliARPA-SIM - HydroMeteorological Service of Emilia-
Romagna, Bologna, Italy
limited-area model error: schemes, parameters,
surface forcings
COSMO-SREPS methodology
i.c. and b.c. perturbations -> INM multi-model multi-boundary (SREPS)
model perturbations -> parameter perturbation (fixed value throughout the integration to test the impact of the different parameter perturbations)
LAM ensemble
driving model erroranalysis
error at the global model
scale
larger scale errors
smaller scale errors
System applications
COSMO Priority Project -> Short-Range Ensemble
1D-Var DA of satellite data to provide retrievals to be nudged within 7km COSMO-I7: test of the use of COSMO-SREPS to estimate a flow-dependent B matrix
COSMO-SREPS provides boundary conditions for the ensemble system at 2.8 km under development at DWD (COSMO-DE-EPS)
Involved COSMO people
Marsigli, Montani, Paccagnella (ARPA-SIM): 1.5 FTE
Flora Gofa, Petroula Louka (HNMS): verification, 0.5 FTE
Collaboration:
Susanne Theis, Christoph Gebhardt (DWD): EELMK
Uli Schaettler (DWD): COSMO model code
Task 0. Preliminary actions for the system set-up: completed.
Task 1. Definition of the methodologies to perturb model trajectories: completed
Task 2. Definition of the methodologies to perturb initial conditions: suspended
Task 3. System set-up: completed (set-up for the JJASON 2007 period during the MAP D-PHASE DOP)
Task 4. Test on case studies: on-going (21 runs in autumn 2006 done, analysis on-going)
Task 5. Test on a regular basis: on-going (running on the JJASON 2007 period during the MAP D-PHASE DOP)
Task 6. Verification: on-going
System set-up
16 COSMO runs 10 km
hor. res.40 vertical
levels
COSMO at 25 km on IFS
IFS – ECMWF globalb
y I
NM
S
pain
COSMO at 25 km on GME
GME – DWD global
COSMO at 25 km on UM
UM – UKMO global
COSMO at 25 km on NCEP
AVN – NCEP global
P1: control (ope)
P2: conv. scheme (KF)
P3: tur_len=1000
P4: pat_len=10000
intra-group distance14 days (00UTC runs)
2mT
whole domain
Daily precipitation ROC area
Northern Italy + Switzerland observations
Average over 0.5 x 0.5 deg boxes - +42h fc range
Daily precipitation ROC area
Northern Italy + Switzerland observations
Average over 0.5 x 0.5 deg boxes - +66h fc range
Relationship between error and spread
12UTC runs
Northern Italy observations
Nearest grid point
ensemble mean 2m Temperature nearest grid point
0
1
2
3
4
5
6
7
6 12 18 24 30 36 42 48 54 60 66 72
Forecast time
RM
SE
-6
-4
-2
0
2
4
6
6 12 18 24 30 36 42 48 54 60 66 72
Forecast time
BIA
S
Ensemble member verificationPrecipitation – 0-0.1 mm / 6h
6-hr Accumulative precipitation(interpolation of 9 grid points)
0.8
0.82
0.84
0.86
0.88
0.9
0.92
0.94
0.96
0.98
1
6 12 18 24 30 36 42 48 54 60 66 72
Forecast time
PO
D
YESObs
HitsPOD
IFS
GME
UKMO
NCEP
6-hr Accumulative precipitation(interpolation of 9 grid points)
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
6 12 18 24 30 36 42 48 54 60 66 72
Forecast time
FA
R
YESFc
alarmsFalseFAR
Ensemble member verificationPrecipitation – 0-0.1 mm / 6h
6-hr Accumulative precipitation(interpolation of 9 grid points)
0.8
0.82
0.84
0.86
0.88
0.9
0.92
0.94
0.96
0.98
1
6 12 18 24 30 36 42 48 54 60 66 72
Forecast time
PO
D
Tiedtke, pat_len500
Kain-Fritsch, pat_len500
Tiedtke, tur_len1000, pat_len500
Tiedtke, pat_len10000
6-hr Accumulative precipitation(interpolation of 9 grid points)
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
6 12 18 24 30 36 42 48 54 60 66 72
Forecast time
FA
R
Deterministic scores – ave 0.5 x 0.5 IT+SV
1mm/24h
5mm/24h
10mm/24h
12 UTC
Deterministic scores – ave 0.5 x 0.5 IT+SV
1mm/24h
5mm/24h
10mm/24h
12 UTC
Conclusions
ic and bc perturbations contribute to the spread for an amount approximately double with respect to the parameter perturbations, statistically over the whole domain and the whole period in terms of 2mT. Locally (in space and time) the situation can be quite different
the selected parameters produce a detectable spread among members with the same father
rms error is grater than spread for all the events but the correlation is good
different fathers contribute differently to the skill, for different parameters this is less clear
On-going activities run of COSMO-SREPS with model perturbations for the DOP MAP D-PHASE (6 months, June-November 2007) :
statistical analysis of the system
comparison with the other available mesoscale ensemble systems
verification - system analysis (HNMS)
provide b.c. for DWD ensemble tests
test a flow-dependent B-matrix for 1D-Var of satellite data
test of different parameters (16 runs using only the IFS initial and boundary conditions)
Test of parameter perturbations (same father)
16 LM runs at 10 km
P1: control (ope)
P2: conv. scheme (KF)
P3: parameter 1
P4: parameter 2
P5: …
IFS – ECMWF global
Fine
run nr. parameter name parameter description range default used1 ctrl ope2 lconv convection scheme T or KF T KF3 tur_len maximal turbulent length scale [100,1000] m 500 1504 tur_len maximal turbulent length scale [100,1000] m 500 10005 pat_len length scale of thermal surface patterns [0,10000] m 500 100006 rat_sea ratio of laminar scaling factors for heat over [1,100] 20 17 rat_sea ratio of laminar scaling factors for heat over [1,100] 20 608 qc0 cloud water threshold for autoconversion [0.,0.001] 0 0.0019101112
13 c_lndsurface area density of the roughness elements over land [1,10] 2 1
14 c_lndsurface area density of the roughness elements over land [1,10] 2 10
15 rlam_heat scaling factor of the laminar layer depth [0.1,10] 1 0.116 rlam_heat scaling factor of the laminar layer depth [0.1,10] 1 10
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