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!!!