1. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 The COSMO-LEPS system: getting close to the 5-year milestone Andrea Montani, Chiara Marsigli and Tiziana Paccagnella ARPA-SIM Hydrometeorological service of Emilia-Romagna, Italy IX General COSMO meeting Athens,18-21 September 2007

2. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Outline Motivations Methodology of COSMO-LEPS Verification results: – SYNOP on the GTS Future plans

3. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 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? Because the horizontal resolution of global-model ensemble systems is limited by computer time constraints and does not allow a detailed description of mesoscale and orographic-related processes. The forecast of heavy precipitation events can still be inaccurate (in terms of both locations and intensity) after the short range.

4. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS project  combine the advantages of global-model ensembles with the high-resolution details gained by the LAMs, so as to identify the possible occurrence of intense and localised weather events (heavy rainfall, strong winds, temperature anomalies, snowfall, …) generation of COSMO-LEPS in order to improve the Late-Short (48hr) to Early-Medium (132hr) range forecast of the so-called “severe weather events”.

5. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 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

6. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 The COSMO-LEPS suite @ ECMWF November 2002 – May 2004 d-1 dd+5 d+1d+2 d+4d+3 oldest EPS 12 middle EPS oldest EPS youngest 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 5 Representative Members Driving the 5 COSMO-model integrations COSMO- LEPS Integratio n Domain COSMO- LEPS clustering area

7. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 The COSMO-LEPS suite @ ECMWF June 2004 – January 2006 d-1 dd+5 d+1d+2 d+4d+3 middle EPS youngest 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 COSMO- LEPS Integratio n Domain 10 Representative Members driving the 10 COSMO-model integrations employing either Tiedtke or Kain- Fristch scheme randomly choosen COSMO- LEPS clustering area Suite running in real time at ECMWF managed by ARPA-SIM; Δx ~ 10 km Fc length: 120h

8. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 The new COSMO-LEPS suite @ ECMWF since February 2006 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 COSMO- LEPS Integratio n Domain 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.

9. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Present methodology

10. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Operational set-up Core products:  16 perturbed LM runs (ICs and 3-hourly BCs from 16 EPS members) to generate 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 assess the relative merits between deterministic and probabilistic approach (start at 12UTC;  t = 132h);  1 “hindcast” run (ICs and 3-hourly BCs from ECMWF analyses) to “downscale” ECMWF information (start at 00UTC;  t = 36h).

11. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Dissemination  probabilistic products  deterministic products (individual COSMO-LEPS runs)  derived probability products (EM, ES)  meteograms over station points products delivered at about 1UTC to the COSMO weather services, to Hungary (case studies) and to the MAP D- PHASE and COPS communities (field campaign).

12. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 –SYNOP on the GTS (COSMO-LEPS only); Objective verification of COSMO-LEPS Verification package includes the traditional probabilistic scores: Brier Skill Score (Wilks, 1995) ROC area (Mason and Graham, 1999) Cost-loss Curve (Richardson, 2000) Percentage of Outliers (Buizza, 1997) Ranked Probability Skill Scores (Wilks, 1995)

13. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 –SYNOP on the GTS (COSMO-LEPS only); Objective verification of COSMO-LEPS Main features: variable:12h cumulated precip (18-06, 06-18 UTC); period:from Dec 2002 to Aug 2007; PHASE 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, 50 mm/12h; system:COSMO-LEPS both (57) monthly and (19) seasonal scores are computed. work is in progress for verification over the full domain (1500 stations)

14. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Time series of Brier Skill Score  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.  Equivalent to MSE for deterministic forecast. BSS  improvement of performance detectable for all thresholds along the years;  still problems with high thresholds, but good trend in 2007. fc step: 30-42h Jun04: 5m  10m Feb06: 10m  16m; 32ML  40 ML

15. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Time series of ROC area  Area under the curve in the HIT rate vs FAR diagram.  Valuable forecast systems have ROC area values > 0.6. ROC Jun04: 5m  10m Feb06: 10m  16m; 32ML  40 ML fc step: 30-42h  the positive impact of increasing the ensemble size in 2004 is evident for all thresholds and for different fcst ranges.  poor performance of the system in Spring and Summer 2006 (both particularly dry), despite upgrades. fc step: 78-90h Jun04: 5m  10m Feb06: 10m  16m; 32ML  40 ML

16. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Outliers: time series + seasonal scores  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 5 different Summers (JJA). OUTL  Evident seasonal cycle (more outliers in winter), but overall reduction of outliers in the years. Jun04: 5m  10m Feb06: 10m  16m; 32ML  40 ML  Reduction of outliers from one Summer to the other, related to the increase of ensemble size (more evident for the 5 to 10 increase).  Need to take into account the different statistics for each season (JJA 2003 less rainy than the others).

17. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Semi-diurnal cycle in COSMO-LEPS scores  BSS score … the higher the better …  Performance of the system assessed for 5 different Summers (JJA). BSS  Evident 12-hour cycle in BSS scores (the same holds for RPSS, while less evident for ROC area scores).  Better performance of the system for “night-time” precipitation, that is for rainfall predicted between 18Z and 6Z (ranges 30-42h, 54-66h, …).  The amplitude of the cycle is somewhat reduced throughout the years and with increasing forecast range.  The bad performance in Summer 2006 is confirmed.

18. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Score dependence on the domain size (1)  Verification of COSMO-LEPS against synop reports over the MAP D-PHASE area (~ 470 stations; MAPDOM) and the full domain (~ 1500 stations; fulldom):  different statistics of the verification samples;  up to now, performance of the system over the 2 domains assessed only for the last 6 months (March-August 2007).  difficult to draw general conclusions

19. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Score dependence on the domain size (2) RPSS  RPSS score… the higher the better… (and positive).  ROC area… the higher the better… (and above 0.6).  Smoother transitions from month to month in “fulldom” scores.  Slightly better performance of COSMO-LEPS over the MAPDOM, but the signal varies from month to month.  Higher predictability with orographic forcing?  Need to check individual regions and/or to stratify for type of stations. OUTL ROC  Outliers percentage … the lower the better.

20. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Main results COSMO-LEPS system runs on a daily basis since November 2002 (6 “failures” in almost 5 years of activity) and it has become a “member-state time-critical application” at ECMWF (  ECMWF operators involved in the suite monitoring). COSMO-LEPS products used in EC Projects (e.g. PREVIEW), field campaigns (e.g. COPS, MAP D-PHASE) and met-ops rooms across COSMO community. Nevertheless, positive trends can be identified: increase in ROC area scores and reduction in outliers percentages; positive impact of increasing the population from 5 to 10 members (June 2004); although some deficiency in the skill of the system were identified after the system upgrades occurred on February 2006 (from 10 to 16 members; from 32 to 40 model levels + EPS upgrade!!!), scores are encouraging throughout 2007. Time series scores cannot easily disentangle improvements related to COSMO-LEPS itself from those due to better boundaries by ECMWF EPS. 2 more features: marked semi-diurnal cycle in COSMO-LEPS scores (better skill for “night-time” forecasts); better scores over the Alpine area rather than over the full domain (to be confirmed).

21. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Verification vs synop: assess performance over the full domain and consider other scores (Rank histograms, Reliability diagrams,…). Implement “weighted” derived probability products: –weighted ensemble mean; –weighted ensemble standard deviation. Introduce more model perturbations (see COSMO-SREPS approach). Verification will be further developed → new variables verified. Future plans Implement EFI index in the operational suite? Implement “TIGGE-LAM compliant” COSMO-LEPS which can run on any domain, on any boundary conditions (relocatable COSMO-LEPS). Develop “hybrid” clustering (considering both ECMWF EPS and UKMO MOGREPS) ---> work with GRIB2 format!

22. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Thank you !

23. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 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.

24. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 ENSEMBLE SIZE REDUCTION IMPACT EVALUATED ON CASE STUDIES (1)

25. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 2003082512 Friuli (+72-+96) 20 mm100 mm 5 RMs 10 RMs All 51

26. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 ENSEMBLE SIZE REDUCTION IMPACT EVALUATED ON CASE STUDIES (2) Observed precipitation between 15-11-2002 12UTC and 16-11-2002 12 UTC Piedmont case

27. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 2002111212 Piedmont 20 mm150 mm 5 RMs 10 RMs All 51

28. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS Real time products

29. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Operational COSMO-LEPS ~Operational EPS “Friuli case” S.E. 153 5 RMs The youngest EPS

30. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 >20mm/24h>50mm/24h Operational COSMO-LEPS ~Operational EPS : Friuli case probability maps – fc. range +96 COSMO LEPS EPS 51 members

31. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 old suite new suite BSS outliers EVALUATION OF S.E. SIZE (either 51, or 102, or 153) & ENSEMBLE SIZE REDUCTION (either 5 or 10 RMs)  Regarding the 5-RM ensembles results would seem to suggest that the use of just two EPS in the super- ensemble can be a good compromise, permitting to decrease the percentage of outliers significantly with respect of using just 1 EPS but leading only to a small decrease of the skill.  Regarding the impact of the ensemble size, the difference between each 5-member ensemble and the correspondent 10-member ensemble is remarkable.The impact of doubling the ensemble size is almost the same for every configuration and is larger than impact of changing the number of EPSs on which the Cluster Analysis is performed (2 or 3).

32. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 TEST OF NEW CLUSTERING VARIABLES AND/OR DIFFERENT CLUSTERING INTERVALS  Consider a fixed configuration in terms of ensemble size (10 RMs selected out of 2 EPS sets, 2eps-10rm) and the properties of the “reduced” (10-member) global ensemble in 4 different cases: OPE:the 10 members are selected like in the operational set-up (clustering variables: z,u,v,q; clustering levels: 500, 700, 850 hPa; clustering times: fc+96h, fc+120h); D2: like OPE, but clustering times: fc+24h, fc+48h; D3: like OPE, but clustering times: fc+48h, fc+72h; D4: like OPE, but clustering times: fc+72h, fc+96h. BSS Brier Skill Score: OPE has slightly better scores at all verification ranges (less evident for ROC area.. not shown); Outliers percentage: results heavily depends on the verification range. outliers

33. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS derived probability products The generation of the Ensemble Mean (EM) and Ensemble Standard deviation (ES) was implemented and tested for COSMO-LEPS runs in terms of: Z700 - T850 – MSLP - T2M - UV10M - TP from fc+0h to fc+132h every 3 hours Dissemination will start at the end of the month. EM and ES are calculated without considering the weights relative to each integration.

34. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Why Limited Area Ensemble Prediction? Global Ensemble Prediction Systems –have become extremely important tools to tackle the problem of predictions beyond day 2 –are usually run at a coarser resolution with respect to deterministic global predictions → skill in forecasting intense and localised events is currently still limited.

35. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Why Limited Area Ensemble Prediction? (2) As regards high resolution deterministic forecast in the short range, where limited-area models play the major role, a “satisfactory” QPF is still one of the major challenges. The same can be said for other local parameters. This is due, among other reasons, to the inherently low degree of predictability typical of severe and localised events. Probabilistic/Ensemble approach is so required also for the short range at higher resolution

36. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 From Global EPS to LAM EPS In the Limited-area ensemble systems, tailored for the short range, perturbations must be already “active” during the first hours of integration The characteristic of the LAM ensemble are strongly dependent by the lateral boundaries forcing. Due to the “regional” application of these Limited Area Ensembles, methodologies can be different in different geographycal regions. A pratical consideration: Global EPS ~ Big Centres Limited Area EPS ~ (also) Relatively Small Centres

37. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 In the last period the verification package is being developed keeping into account two measure of precipitation:  the cumulative volume of water deployed over a specific region  the rainfall peaks which occur within this region OBJECTIVE VERIFICATION OF COSMO-LEPS COSMO observations

38. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 CLEPSEPS Verification grid OBS MASK

39. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Archiving of C0SMO-LEPS From July 2005, products are archived on MARS at ECMWF  Deterministic run (fc+0h to fc+132h every 3h).  Ensemble Prediction System:  16 perturbed forecasts (fc+0h to fc+132h every 3h): PLEV (500, 700, 850 hPa): Z, RH, T. SURF: albedo, LCC, MCC, TCC, SW radiation flux, CAPE, hzerocl, snowlmt, mslp, T_2m, Td_2m, TMAX_2m, TMIN_2m, U_10m, V_10m, UVMAX_10m, large-scale rain, convective rain, large-scale snow, TP.  Forecast probability (various intervals and thresholds): SURF: CAPE, hzerocl, TMAX_2m, TMIN_2m, UVMAX_10m, TP, snowfall, showalter index.  Clustering information (population, clustering variable used, …).  Derived products (fc+0h to fc+132h every 3h): ens-mean and ens-spread: Z700, T850, MSLP, T2M, UV10M, TP.

40. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS 16-MEMBER EPS 51-MEMBER EPS tp > 1mm/24h tp > 5mm/24h Average values boxes 0.5x0.5 deg 3 sis

41. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS 16-MEMBER EPS tp > 1mm/24h NOCC=610 NOCC=1195 tp > 5mm/24h NOCC=2671 tp > 10mm/24h ave 0.5

42. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Maximum values boxes 0.5x0.5 deg tp > 1mm/24h tp > 5mm/24h tp > 10mm/24h COSMO-LEPS 16-MEMBER EPS 51-MEMBER EPS 3 sis

43. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS 16-MEMBER EPS tp > 20mm/24h NOCC=227 Average values boxes 0.5x0.5 deg

44. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Precipitation: average on 1.5 x 1.5 boxes tp > 10mm/24htp > 20mm/24h COSMO-LEPS 5-MEMBER EPS 51-MEMBER EPS SON 2003 ROC area  As regards AVERAGE precipitation above these two threshols, EPS wins.  Worsening due to the ensemble reduction  Positive impact of LM downscaling

45. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 maxima on 1.5 x 1.5 boxes tp > 20mm/24h COSMO-LEPS 5-MEMBER EPS 51-MEMBER EPS tp > 50mm/24h SON 2003 ROC area  COSMO-LEPS is more skilful than EPS in forecasting correctly high precipitation values over a rather large area. Number of occurrences: 600 (20 mm threshold) and 150 (50 mm).

46. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Time series of ROC area for COSMO-LEPS (2)  Area under the curve in the FAR vs HIT diagram.  Valuable forecast systems have ROC area values > 0.6 ROC  the positive impact of increasing the ensemble size in 2004 is evident for all thresholds and for different fcst ranges.  poor performance of the system in Spring and Summer 2006, despite system upgrades. Jun04: 5m  10m Feb06: 10m  16m; 32ML  40 ML fc step: 78-90h

47. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS 16-MEMBER EPS 51-MEMBER EPS Average values (boxes 0.5 x 0.5 deg) MAM06

48. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Time series of TEST OF NEW CLUSTERING VARIABLES AND/OR DIFFERENT CLUSTERING INTERVALS  Consider a fixed configuration in terms of ensemble size (10 RMs selected out of 2 EPS sets, 2eps-10rm) and the properties of the “reduced” (10-member) global ensemble in 4 different cases: OPE:the 10 members are selected like in the operational set-up (clustering variables: z,u,v,q; clustering levels: 500, 700, 850 hPa; clustering times: fc+96h, fc+120h); D2: like OPE, but clustering times: fc+24h, fc+48h; D3: like OPE, but clustering times: fc+48h, fc+72h; D4: like OPE, but clustering times: fc+72h, fc+96h. BSS Brier Skill Score: OPE has slightly better scores at all verification ranges (less evident for ROC area.. not shown); Outliers percentage: results heavily depends on the verification range. outliers

49. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Main results COSMO-LEPS system runs on a daily basis since November 2002 and it has become a “member-state time-critical application” at ECMWF (  partial involvement of ECMWF operators in the suite management). Time series scores identify positive trends in the performance of the system: increase in ROC area scores and reduction in outliers percentages; positive impact of increasing the population from 5 to 10 members (June 2004); some deficiency in the skill of the system identified after the system upgrades occurred on February 2006 (from 10 to 16 members; from 32 to 40 model levels + EPS upgrade!!!)  need of further investigation. High-resolution verification shows better scores of COSMO-LEPS with respect to EPS in forecasting precipitation maxima within boxes. No clear impact of the weighting procedure as regards precipitation, BUT COSMO-LEPS ensemble mean for 2m temperature has better skill (lower standard deviation to observations) with weighting the ensemble members according to cluster populations compared to the mean with unweighted members.

50. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Downscaling Global Ensemble LAM Nesting GCM membersLAM members Total Downscaling (Brute-Force Approach) Global Ensemble LAM Nesting GCM members LAM members Ensemble Size Reduction Representative members COSMO LEPS Approach

51. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS forecast for 72h precipitation by AW (Meteoswiss)

52. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Probability precipitation > 250mm/72h C. Frei, MeteoSwiss by AW (Meteoswiss)

53. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Standard deviation: 2m temperature 12UTC Forecast range (h) DJF 2004/2005 JJA 2005 STD 2 = RMS 2 – BIAS 2 uw: unweighted / w: weighted according to cluster population 0C0C 0C0C

54. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS NW COSMO-LEPS W tp > 1mm/24h COSMO-LEPS weighting procedure maximum values (boxes 0.5x0.5 deg)

55. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Outliers: time series + seasonal scores  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 for 4 different Autumns. OUTL  Continuous reduction of outliers from one year to the other, also related to the increase of ensemble size (more evident for the 5 to 10 increase, rather than from 10 to 16).  Need to take into account the different statistics for each season (SON 2006 less rainy than the others). Jun04: 5m  10m Feb06: 10m  16m; 32ML  40 ML

56. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS NW COSMO-LEPS W tp > 1mm/24h COSMO-LEPS weighting procedure maximum values (0.5x0.5 boxes) average values (0.5x0.5 boxes) tp > 1mm/24h

57. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Synop-Verification: COSMO-LEPS & aLMo aLMo domain Common verification domain, about 1000 synop stations aLMo:- deterministic 7 km model (45 levels) of MeteoSwiss for 72h forecasts - same code (LM) as COSMO-LEPS by AW (Meteoswiss)

58. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Standard deviation: 2m temperature 00UTC Forecast range (h) DJF 2004/2005 JJA 2005 w 0C0C 0C0C STD 2 = RMS 2 – BIAS 2 uw: unweighted / w: weighted according to cluster population by AW (Meteoswiss)

59. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Case study: flood event in Switzerland in August 2005 Photos:Tages-Anzeiger Courtesy of Andrè Walser (Meteoswiss)

60. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Synoptic overview: 22 August 2005 Temperature 850 hPa and geopotential 500 hPa: 2º2º 18º 10º by AW (Meteoswiss)

61. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Total precipitation over 3 days (20/8 – 23/8) About 400 stations, precipitation sum locally over 300 mm! (06 - 06 UTC) C. Frei, MeteoSwiss by AW (Meteoswiss)

62. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS forecast for 72h precipitation by AW (Meteoswiss)

63. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS vs ECMWF EPS probability of 72h cumulated precipitation by AW (Meteoswiss)

64. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Probability precipitation > 100mm/72h C. Frei, MeteoSwiss by AW (Meteoswiss)

65. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Probability precipitation > 100mm/72h C. Frei, MeteoSwiss by AW (Meteoswiss)

66. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 –high-resolution network (COSMO-LEPS vs ECMWF EPS) Objective verification of COSMO-LEPS Main features: variable:24h cumulated precip (06-06 UTC); period:MAM 2006; region:Germany, Switzerland, Italy; method: BOXES (0.5 x 0.5); obs: COSMO network (2500 stations x day); fcst ranges: 18-42h, 42-66h, 66-90h, 90-114h; thresholds: 1, 5, 10, 20, 50 mm/24h; systems: - COSMO-LEPS(16m, 10 km, 40 ML) - reduced EPS(16m, 50 km, 60 ML) - full EPS (51m, 50 km, 60 ML)

67. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 Verification of the distributions Station observation Grid point forecast The verification has been made in terms of: Average value Maximum value 50th percentile (Median) 90th percentile in a box two measures of precipitation:  the cumulative volume of water deployed over a specific region;  the rainfall peaks occurring within the same region.

68. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 tp > 1mm/24h tp > 5mm/24h Maximum values (boxes 0.5 x 0.5) COSMO-LEPS 16-MEMBER EPS 51-MEMBER EPS tp > 10mm/24h NOCC=3681 NOCC=1592 NOCC=2492 MAM06

69. A.Montani; The COSMO-LEPS system: 5-year milestone COSMO meeting, Athens, 18-21 September 2007 COSMO-LEPS 16-MEMBER EPS 51-MEMBER EPS Maximum values (boxes 0.5 x 0.5) MAM06  COSMO-LEPS is more skilful than EPS in forecasting correctly high precipitation values over 0.5 x 0.5 boxes.