1. A.Montani; The COSMO-LEPS system. COSMO-LEPS: present status and plans Andrea Montani, C. Marsigli, T. Paccagnella ARPA-SIMC HydroMeteoClimate Regional Service of Emilia-Romagna, Bologna, Italy COSMO General meeting Sibiu, 2-5 September 2013

2. A.Montani; The COSMO-LEPS system. Outline Present status of COSMO-LEPS:  about the operational verification,  about the calibrated precipitation,  about the convection schemes,  about the clustering technique,  about the future plans.

3. A.Montani; The COSMO-LEPS system. COSMO-LEPS suite @ ECMWF: present status d-1 dd+5 d+1d+2 d+4d+3 older EPS younger EPS clustering period 00 12 Cluster Analysis and RM identification 4 variables Z U V Q 3 levels 500 700 850 hPa 2 time steps Cluster Analysis and RM identification European area Complete Linkage 16 Representative Members driving the 16 COSMO-model integrations (weighted according to the cluster populations) using either Tiedtke or Kain-Fristch convection scheme (members 1-8 T, members 9-16 KF) + perturbations in turbulence scheme and in physical parameterisations COSMO- LEPS clustering area suite runs twice a day (00 and 12UTC) as a “time-critical application” managed by ARPA- SIMC; Δx ~ 7 km; 40 ML; fc+132h; COSM0 v4.26 since Jan 2013; computer time (50 million BUs for 2013) provided by the ECMWF member states in COSMO. COSMO- LEPS Integration Domain

4. A.Montani; The COSMO-LEPS system. Main changes during the COSMO year 16 January 2013 : COSMO upgrade: 4.21  4.26; int2lm upgrade: 1.18  1.20. 17 January 2013: operational dissemination implemented for ARPA-Veneto. 22 January 2013, technical changes at ECMWF: change of ECMWF super-computer and of the user running the suite: itm  zcl; introduction of a new “dissemination stream” for COSMO-LEPS: “ad-hoc” initial and boundary conditions do not have to be retrieved any more, but are prepared on a dedicated file system; product dissemination starts about 40 minutes earlier than before (at 9UTC and 21UTC). 7 May 2013: enriched test dissemination implemented for HNMS. 13 May 2013: in the framework of GEOWOW research project, COSMO- LEPS was the first system to populate TIGGE-LAM archive at ECMWF (high- priority parameters in grib2 format). 25 June 2013: tests with Fieldextra 11.1.0 started.

5. A.Montani; The COSMO-LEPS system. Outline Present status of COSMO-LEPS:  about the operational verification,

6. A.Montani; The COSMO-LEPS system. –SYNOP on the GTS Time-series verification of COSMO-LEPS Main features: variable: 12h cumulated precip (18-06, 06-18 UTC); period : from Dec 2002 to Jul 2013; PHASE region: 43-50N, 2-18E (MAP D-PHASE area); method: nearest grid point; no-weighted fcst; obs: synop reports (about 470 stations/day); fcst ranges: 6-18h, 18-30h, …, 102-114h, 114-126h; thresholds: 1, 5, 10, 15, 25, 50 mm/12h; system: COSMO-LEPS; scores: ROC area, BSS, RPSS, Outliers, … both monthly and seasonal scores were computed

7. A.Montani; The COSMO-LEPS system. Brier Skill Score: time series and seasonal scores  BSS is written as 1-BS/BS ref. Sample climate is the reference system. Useful forecast systems if BSS > 0.  BS measures the mean squared difference between forecast and observation in probability space.  Performance of the system assessed as time series (6-month running mean) and for the last 4 springs (MAM).  Seasonal scores for a fixed event (“12h precip > 10mm”): need to take into account the different statistics for each season (last MAM was the wettest).  Best performance for the last spring, with BSS positive for all forecast ranges.  Time series: high month- to-month variability, but a positive trend can be noticed.  Good scores in 2012 and 2013; BSS positive for all thresholds since April 2009; fewer and fewer problems with high thresholds.

8. A.Montani; The COSMO-LEPS system. Outline Present status of COSMO-LEPS:  about operational verification (time-series scores show improvements),  about the calibrated precipitation;

9. A.Montani; The COSMO-LEPS system. about calibrated precipitation For each COSMO-LEPS member, calibrated precipitation is operationally generated over Germany, Switzerland and Emilia-Romagna; the calibration technique is based on CDF-based corrections, making use of COSMO-LEPS reforecast. For MAM2013, inter-comparison between raw and calibrated 24h TP forecast. Main features: variable: 24h cumulated precip (06-06 UTC); period : DJF 2012-13 and MAM 2013; region: Germany, Switzerland, Emilia-Romagna; method: nearest grid point; no-weighted fcst; obs: synop reports (about 300 stations/day); fcst ranges: 18-42h, 42-66h, 66-90h, 90-114h; thresholds: 1, 5, 10, 15, 25, 50 mm/12h; system: opecleps and Calibcleps; scores: ROC area, BSS, RPSS, Outliers, RelDiag, …

10. Cumulative Distribution Function based corrections Ref: Zhu and Toth, 2005 AMS Annual Conf., and many others For each model grid point: blue line  CDF of COSMO-LEPS reforecasts red line  CDF of historical observations “raw forecast”  each member of the operational COSMO-LEPS Calibration strategy – methodologies

11. A.Montani; The COSMO-LEPS system. opecleps vs Calibcleps fc 42-66h; 10mm/24h

12. A.Montani; The COSMO-LEPS system. Outline Present status of COSMO-LEPS:  about operational verification (time-series scores show improvements),  about calibration (positive impact, especially over Emilia-Romagna);  about convection schemes;  about the clustering technique ;  about the future plans.

13. A.Montani; The COSMO-LEPS system. Adapt COSMO-LEPS suite to ECWMF forthcoming upgrades: –increase of vertical resolution in ECMWF-EPS: 62  91; –change of Member-State server: ecaccess  ecgb; –change of super-computer: IBM  Cray. Keep an eye (possibly, two) to the performance of ECMWF EPS. Carry on study about the clustering methodology. about the future plans Support verification with Versus. Analysis of the performance of COSMO-HYBEPS (COSMO-LEPS + 2-3 COSMO runs nested on IFS/GME/GFS): tests ongoing. Increase of COSMO-LEPS vertical resolution (40  50ML): tests start in October. Use of high-resolution ECMWF-EPS boundaries (LAMEPS_BC project): tests start by the end of 2013.

14. A.Montani; The COSMO-LEPS system. Thank you for the attention !

15. A.Montani; The COSMO-LEPS system. Extra slides on configuration European Conference on Applications of Meteorology / EMS annual meeting 09 – 13 September 2013, Reading (UK) Session NWP4 (on 13 September) : Probabilistic and ensemble forecasting at short and and medium-range http://www.ems2013.net/home.html

16. A.Montani; The COSMO-LEPS system. Dim 2 Initial conditions Dim 1 Dim 2 Possible evolution scenarios Dim 1 Initial conditions ensemble size reduction Cluster members chosen as representative members (RMs) LAM integrations driven by RMs LAM scenario COSMO-LEPS methodology

17. A.Montani; The COSMO-LEPS system. COSMO-HYBrid Ensemble Prediction System From the results of CONSENS PP, come to a synthesis with the different ensemble systems / strategies, considering scientific, implementation, solidity aspects. Generate 20-member hybrid ensemble (COSMO-HYBEPS), where: a) 16 members comes from COSMO-LEPS, b) 1 member is nested on IFS (uses Tiedtke scheme), c) 1 member is nested on IFS (uses Kain-Fritsch scheme), d) 1 member is nested on GME, e) 1 member is nested on GFS. already existing taken from CONSENS. All members have Δx ~ 7 km; 40 ML; fc+132h; Study performance of different members’ combinations with the same ensemble size. “20-members esuite” implemented on 7/9/2012; will be run up to the end of the year

18. A.Montani; The COSMO-LEPS system. COSMO-LEPS (developed at ARPA-SIM) What is it? It is a Limited-area Ensemble Prediction System (LEPS), based on COSMO-model and implemented within COSMO (COnsortium for Small-scale MOdelling, which includes Germany, Greece, Italy, Poland, Romania, Switzerland). Why? It was developed to combine the advantages of global-model ensembles with the high-resolution details gained by the LAMs, so as to identify the possible occurrence of severe and localised weather events (heavy rainfall, strong winds, temperature anomalies, snowfall, …) generation of COSMO-LEPS to improve the Late-Short (48hr) to Early-Medium (132hr) range forecast of severe weather events.

19. A.Montani; The COSMO-LEPS system. Operational set-up Core products:  16 perturbed COSMO-model runs (ICs and 3-hourly BCs from 16 EPS members) to generate, “via weights”, probabilistic output: start at 12UTC;  t = 132h; Additional products:  1 deterministic run (ICs and 3-hourly BCs from the high- resolution deterministic ECMWF forecast) to “join” deterministic and probabilistic approaches: start at 12UTC;  t = 132h;  1 hindcast (or proxy) run (ICs and 3-hourly BCs from ECMWF analyses) to “downscale” ECMWF information: start at 00UTC;  t = 36h.

20. A.Montani; The COSMO-LEPS system. Types of perturbations As for types and values, the results from CSPERT experimentation were followed (* denotes default values for COSMO v4.26 ): convection_scheme: Tiedtke* (members 1-8), Kain-Fritsch (members 9-16), tur_len (either 150, or 500*, or 1000), pat_len (either 500*, or 2000), crsmin (either 50, or 150*, or 200), rat_sea (either 1, or 20*, or 40), rlam_heat (either 0.1, or 1*, or 5), mu_rain : either 0.5* (with rain_n0_factor =0.1) or 0 (with rain_n0_factor =1.0), cloud_num (either 5x10^8* or 5x10^7).

21. convection scheme: T=Tiedtke KF=Kain-Fritsch; tur_len: maximal turbulent length scale (default 500m); this parameter is used mainly in the calculation of the characteristic length scale for vertical mixing and thus into the calculation of the vertical transport momentum coefficient; pat_len: length scale of thermal surface patterns (default 500m); this parameter is mainly used in the calculation of the large-scale part of the equation addressing the heat flux parameterisation; horizontal length; rlam_heat: scaling factor of the laminar layer depth (default 1); it defines the layer with non- turbulent characteristics (molecular diffusion effects only); rat_sea: ratio of laminar scaling factors for heat over sea (default 20); crsmin: minimal stomata resistance (default 150); Cloud_num: Cloud droplet number concentration; Mu_rain: Exponent of the raindrop size distribution; ( gscp: Switch on/off of the graupel scheme).

22. A.Montani; The COSMO-LEPS system. Main results Time-series verification ECMWF EPS changed substantially in the last years (more and more weight to EDA- based perturbations) and it is hard to disentangle improvements related to COSMO- LEPS upgrades from those due to better boundaries; nevertheless: –high values of BSS and ROC area for the probabilistic prediction of 12-h precipitation for autumn 2011; –poor performance in the first months of 2012, then recovery. Need to investigate what happened. Case-study verification Consistent signal for different forecast ranges of a high-impact weather event for the snowfalls of February 2012.

23. A.Montani; The COSMO-LEPS system. Extra slides on verification

24. A.Montani; The COSMO-LEPS system. Time series of ROC area (6-month running mean)  Area under the curve in the HIT rate vs FAR diagram; the higher, the better …  Valuable forecast systems have ROC area values > 0.6.  Highest scores in the 2 nd part of 2011 and, for the highest threshold, in 2013. Positive trend through the years can be noticed.  Drier seasons during 2011 and 2012 with few heavy- precipitation events: limited significance of the results for the 15mm threshold.  Limited loss of predictability with increasing forecast range (not shown).

25. A.Montani; The COSMO-LEPS system. Seasonal scores of ROC and BSS: last 4 springs  Fixed event (“12h precip > 10mm”): consider the performance of the system for increasing forecast ranges.  Valuable forecast systems have ROC area values > 0.6 and BSS > 0.  Need to take into account the different statistics for each season (MAM 2011 was the driest).  Best performance for the spring 2011 and 2013, but less marked diurnal cycle in 2013.  Spring 2013: BSS is positive for all forecast ranges  Similar results for the other thresholds (not shown).

26. A.Montani; The COSMO-LEPS system. Outliers: time series + ………seas scores (DJF)?  How many times the analysis is out of the forecast interval spanned by the ensemble members.  … the lower the better …  Performance of the system assessed as time series and for the last 4 winters.  Evident seasonal cycle (more outliers in winter).  Overall reduction of outliers in the years up to 2007; then, again in 2009 and 2010, but later.  Need to take into account the different statistics for each season.  In the short range, best results for winter 2010- 2011.  For longer ranges, the performance of the system is “stable”.  Outliers before 10% from day 3 onwards.

27. A.Montani; The COSMO-LEPS system. Seasonal scores of BSS: ……last 4 winters  Fixed event (“12h precip > 10mm”): consider the performance of the system for increasing forecast ranges.  Fixed forecast range (fc 30-42h): consider the performance of the system for increasing thresholds.  Need to take into account the different statistics for each season (last DJF was the driest).  Fixed event: best performance for the last two winters (ECMWF EPS had a record performance for winter 2009-2010): BSS positive for all forecast ranges.  Fixed forecast range: similar results as before.  Similar results for longer forecast ranges and for higher thresholds.

28. A.Montani; The COSMO-LEPS system. Ranked Probability Skill Score: time series + …….. seasonal scores (MAM)  A sort of BSS “cumulated” over all thresholds. RPSS is written as 1-RPS/RPS ref. Sample climate is the reference system. RPS is the extension of the Brier Score to the multi-event situation.  Useful forecast systems for RPSS > 0.  Performance of the system assessed as time series and for the last 4 springs (MAM).  the increase of the COSMO-LEPS skill is detectable for 3 out of 4 forecast ranges along the years, BUT  low skill in the first months of 2012 (the problem comes from MAM), then recovery.  Best results for MAM 2011; quick decrease of RPSS with fcst range for MAM 2012.

29. A.Montani; The COSMO-LEPS system. Bias and rmse of T2M Ensemble Mean  Consider bias (the closer to zero, the better) and rmse (the lower the better).  Bias closer to zero (0.5 °C of decrease) and lower rmse for the 7-km suite.  The improvement is not “massive”, but detectable for all forecast ranges, especially for day-time verification.  The signal is stable (similar scores for 1-month or 3-month verification).  Need to correct T2M forecasts with height to assess the impact more clearly.

30. A.Montani; The COSMO-LEPS system. Overestimation of Td 2m and soil moisture (1)  Verification period: MAM07 and MAM08.  Obs: synop reports (about 470 stations x day).  Region: 43-50N, 2-18E (MAP D-PHASE area).  Larger bias and larger rmse in MAM08 rather than in MAM07 for COSMO-LEPS deterministic run (in 2007, no multi- layer soil model).

31. A.Montani; The COSMO-LEPS system. Extra slides on LAMEPS-BC

32. A.Montani; The COSMO-LEPS system. Test data for LAMEPS Boundary Conditions

33. A.Montani; The COSMO-LEPS system. Outline Introduction:  migration to the 7-km system. COSMO-LEPS 10 km (old) COSMO-LEPS 7 km (new)

34. A.Montani; The COSMO-LEPS system. COSMO-LEPS 16-MEMBER EPS 51-MEMBER EPS tp > 1mm/24h tp > 5mm/24h Average values (boxes 0.5 x 0.5) MAM06  As regards AVERAGE precipitation above these two threshols, the 3 systems have similar performance.

35. A.Montani; The COSMO-LEPS system. opecleps vs Calibcleps fc 42-66h; 1mm/24h fc 42-66h; 10mm/24h

36. A.Montani; The COSMO-LEPS system. Outline Present status of COSMO-LEPS:  about operational verification (time-series scores show improvements),  about calibration (positive impact, especially over Emilia-Romagna!);  about convection schemes, members 1-8 use Tiedtke convection scheme (8TD), members 9-16 use Kain-Fritsch (8KF). MAM 2013: compare cleps16, 8TD, 8KF.

37. A.Montani; The COSMO-LEPS system. about the convection scheme BSS, tp > 1mm ROC, tp > 10mm ROC, tp > 1mm BSS, tp > 10mm As expected, best performance by the full ensemble (cleps16). Tiedtke-members better than Kain-Fritsch members, but NOT for all scores. ___ cleps16 ___ 8TD ___ 8KF

38. A.Montani; The COSMO-LEPS system. about the clustering technique AIM: provide limited-area ensembles (either convection-parameterised or convection-permitting) with the best set of boundary conditions. Study different types of clustering analyses (over the same area, grid): ope: use two 12-hourly-lagged EPS, steps=96/120 (108/132) for the younger (older) EPS, variables=Z/U/V/Q, levels=500/700/850 hPa; rnd0: use the younger EPS and always select members 0 to 15 (0 denotes the control member) rnd1 : like rnd0, but select members 1 to 16.... Analyse properties (e.g. spread, skill) of the 16-member global ensembles for several upper-air variables  Outcome: modifications to the number of clusters / number of EPS considered / clustering intervals.

39. A.Montani; The COSMO-LEPS system. Test modifications of clustering methodology Consider distances between ECMWF EPS members according to “COSMO-LEPS metric” (Z, U, V, Q in the mid-lower troposphere over the clustering domain). Look at distances between pairs of ECMWF EPS members; to what extent these distances grow with forecast range, using “COSMO- LEPS metric”? Study a number of seasons.  Outcome: modifications to the number of clusters / number of EPS considered / clustering intervals.

40. A.Montani; The COSMO-LEPS system. Extra slides on COSMO-S14-EPS

41. A.Montani; The COSMO-LEPS system. Important ingredients (from 1 st and 2 nd FROST meetings) 1.Provide reasonable “numbers”.  addressed 2.Develop experience with probabilities. ? 3.Feedback on the top-priority products.  being addressed 4.Snow analysis. ? 5.Soil-field initialisation.  addressed 6.High-res obs to assess the quality of the system.  being addressed 7.Computer time.  addressed 8.Timeliness in product delivery.  addressed 9....... anything to add/remove?

42. A.Montani; The COSMO-LEPS system. FROST-2014 vs SOCHMEL 1)Introduction to FROST-2014: a)What is it? b)What has to do with COSMO? 2)COSMO ensemble activities within FROST-2014: a)introduction to SOCHMEL (the SOCHi-targeted Mesoscale EnsembLe system) b)methodology; c)phases of development; d)planned activity. 3)Final remarks.