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Ensemble activities in COSMO

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

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Ensemble activities in COSMO

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  1. Ensemble activities in COSMO C. Marsigli, A. Montani, T. Paccagnella ARPA-SIM - HydroMeteorological Service of Emilia-Romagna, Bologna, Italy

  2. 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

  3. The COSMO-LEPS suite @ ECMWF 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) 3 levels 500 700 850 hPa 4 variables Z U V Q d+3 d+4 d d+5 d+1 d+2 d-1 Cluster Analysis and RM identification Cluster Analysis and RM identification older EPS 00 2 time steps younger EPS 12 European area clustering period Complete Linkage 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 clustering area COSMO-LEPS Integration Domain

  4. 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-PHASE 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, 50mm/12h; both monthly and seasonal scores are computed. work is in progress for verification over the full domain (1500 stations)

  5. Time series of Brier Skill Score Jun04: 5m  10m Feb06: 10m16m; 32ML  40 ML fc. range 30-42h

  6. Time series of Brier Skill Score Feb06: 10m16m; 32ML  40 ML Jun04: 5m  10m fc. range 78-90h

  7. Jun04: 5m  10m Feb06: 10m  16m; 32ML  40 ML Time series of ROC area fc. range 30-42h

  8. Feb06: 10m  16m; 32ML  40 ML Jun04: 5m  10m Time series of ROC area fc. range 78-90h

  9. Feb06: 10m  16m; 32ML  40 ML Jun04: 5m  10m Outliers: time series Theoretical value

  10. COSMO-LEPS summer over the years

  11. Comparison with EPS average 95th percentile MAM 2006 boxes maximum

  12. Comparison with EPS average 95th percentile 66-90 h 66-90 h MAM 2006 boxes maximum 66-90 h

  13. Setup 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) COSMO-LEPS Climatology F. Fundel, A. Walser, M. Liniger, C. Appenzeller

  14. 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 Probability of Return Period exceedance • PRP1 = Event that happens once per September • PRP100 = Event that happens in one out of 100 Septembers COSMO-PRP2 F. Fundel, A. Walser, M. Liniger, C. Appenzeller

  15. COSMO-SREPS larger scale errors driving model error analysis error at the global model scale LAM ensemble limited-area model error: schemes, parameters, surface forcings smaller scale errors • 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)

  16. IFS – ECMWF global System set-up COSMO at 25 km on IFS P1: control (ope) P2: conv. scheme (KF) P3: tur_len=1000 P4: pat_len=10000 GME – DWD global COSMO at 25 km on GME by INM Spain 16 COSMO runs 10 km hor. res. 40 vertical levels UM – UKMO global COSMO at 25 km on UM AVN – NCEP global COSMO at 25 km on NCEP

  17. 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

  18. Relationship between error and spread Northern Italy observations Nearest grid point 12UTC runs

  19. intra-group distance14 days (00UTC runs) 2mT whole domain

  20. Daily precipitation - ROC area Northern Italy + Switzerland observations Average over 0.5 x 0.5 deg boxes - +42h fc range

  21. IFS GME NCEP UKMO Ensemble member verificationPrecipitation – 0-0.1 mm / 6h F. Gofa, P. Louka

  22. Tiedtke, pat_len500 Kain-Fritsch, pat_len500 Tiedtke, tur_len1000, pat_len500 Tiedtke, pat_len10000 Ensemble member verificationPrecipitation – 0-0.1 mm / 6h F. Gofa, P. Louka

  23. IFS – ECMWF global 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 P1: control (ope) P2: conv. scheme (KF) P3: parameter 1 P4: parameter 2 P5: …

  24. 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-SREPS MAP D-PHASE: ensemble intercomparison!!!

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