Ensemble activities in COSMO
C. Marsigli, A. Montani, T. Paccagnella
ARPA-SIM - HydroMeteorological Service of Emilia-Romagna, Bologna, Italy
Outline
COSMO-LEPS -> early medium range
5 year verification
re-forecasting (MeteoSwiss)
COSMO-SREPS -> short-range
error vs spread
role of the different perturbations
verification (HNMS, Greece)
future plans
The COSMO-LEPS suite @ ECMWF
d-1d-1dd d+5d+5d+1d+1 d+2d+2 d+4d+4d+3d+3
older EPSolder EPS
younger EPSyounger EPS
clustering clustering periodperiod
0000
1212
Cluster Analysis and RM identificationCluster Analysis and RM identification
4 variables4 variables
Z U V QZ U V Q
3 levels3 levels
500 700 850 hPa500 700 850 hPa
2 2 time time stepssteps
Cluster Analysis and RM identificationCluster Analysis and RM identification
European European areaarea
Complete Complete LinkageLinkage
16 Representative Members driving the
16 COSMO-model integrations
(weighted according to the cluster populations)
employing either Tiedtke or Kain-
Fristch convection scheme (randomly
choosen)
COSMO-LEPS
clustering area
suite running as a ”time-critical application” managed by ARPA-SIM;Δx ~ 10 km; 40 ML;COSM0-LM 3.20 since Nov06;fc length: 132h;Computer time (4.3 million BU for 2007) provided by the COSMO partners which are ECMWF member states.
COSMO-LEPS
Integration
Domain
5 year verificationsynop data - low density
variable: 12h cumulated precip (18-06, 06-18 UTC);
period: from Dec 2002 to Aug 2007;
region: 43-50N, 2-18E (MAP D-PHASEPHASE
area);
method: nearest grid point; no-weighted fcst;
obs: synop reports (about 470 stations x
day);
fcst ranges: 6-18h, 18-30h, …, 102-114h, 114-126h;
thresholds: 1, 5, 10, 15, 25, 50 mm/12h;both monthly and seasonal scores are computed.
work is in progress for verification over the full domain (1500
stations)
Time series of Brier Skill Score
fc. range 30-42h
Jun04: 5m 10m Feb06: 10m16m; 32ML 40 ML
Time series of Brier Skill Score
fc. range 78-90h
Jun04: 5m 10m
Feb06: 10m16m; 32ML 40 ML
Time series of ROC area
Jun04: 5m 10m Feb06: 10m 16m; 32ML 40 ML
fc. range 30-42h
Time series of ROC area
Jun04: 5m 10m Feb06: 10m 16m; 32ML 40 ML
fc. range 78-90h
Outliers: time series
Jun04: 5m 10m Feb06: 10m 16m; 32ML 40 ML
Theoretical value
COSMO-LEPS summer over the years
Comparison with EPSaverage
maximum
95th percentile
MAM 2006
boxes
Comparison with EPSaverage
maximum
95th percentile
66-90 h
66-90 h
MAM 2006
boxes
66-90 h
COSMO-LEPS ClimatologySetup• Reforecasts over a period of 30 years (1971-
2000)• Deterministic run of COSMO-LEPS (1 member)
(convective scheme = tiedtke)• ERA40 Reanalysis as Initial/Boundary• 42h lead time, 12:00 Initial time• Calculated on hpce at ECMWF• Archived on Mars at ECMWF (surf (30
parameters), 4 plev (8 parameters); 3h step)
• Post processing at CSCS
Limitations• Reforecasts with lead time of 42h are used to
calibrate forecasts of up to 132h• Only one convection scheme (COSMO-LEPS
uses 2)• New climatology needed with each model
version change• Building a climatology is slow and costly• Currently only a monthly subset of the
climatology is used for calibration (warning indices need to be interpreted with respect to the actual month)
F. Fundel, A. Walser, M. Liniger, C. Appenzeller
Approach:• fit a distribution function to the model climate
(e.g. Gamma for precipitation)• find the return levels according to
a given return period• find the number of forecasts exceeding
the return level of a given return period
Return Periods
COSMO-PRP2
•PRP1 = Event that happens once per September
•PRP100 = Event that happens in one out of 100 Septembers
Probability of Return Period exceedance
F. Fundel, A. Walser, M. Liniger, C. Appenzeller
limited-area model error: schemes, parameters,
surface forcings
COSMO-SREPS
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 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
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 COSMO-DE-EPS, the 2.8 km ensemble system under development at DWD
Relationship between error and spread
12UTC runs
Northern Italy observations
Nearest grid point
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
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
F. Gofa, P. Louka
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
F. Gofa, P. Louka
On-going activities
COSMO-SREPS is running for the whole DOP MAP D-PHASE (6 months, June-November 2007)
test of different parameters (16 runs using only the IFS initial and boundary conditions): 3 month run
IFS – ECMWF global
P1: control (ope)
P2: conv. scheme (KF)
P3: parameter 1
P4: parameter 2
P5: …
Future plans
test perturbed parameters within COSMO-LEPS
possibility of using soil parameters from DWD
evaluate the benefit of a system calibration
MAP D-PHASE period runs:
statistical evaluation of the COSMO-SREPS system
verification
selection of the new parameters for COSMO-SREPSMAP D-PHASE: ensemble intercomparison!!!