A.Montani; The COSMO-LEPS system. Recent developments and plans for the COSMO-LEPS system Andrea Montani, C. Marsigli, T. Paccagnella ARPA-SIMC HydroMeteoClimate Regional Service of Emilia-Romagna, Bologna, Italy COSMO General meeting Lugano, September 2012

A.Montani; The COSMO-LEPS system. Outline Recent upgrades of COSMO-LEPS:  implementation of 00UTC COSMO-LEPS,  modifications in the set-up of members’ perturbations,  implementation of calibrated precipitation. Performance of the system:  time-series verification of COSMO-LEPS using SYNOP,  case study assessment (“nevone 2012”). Present/future work:  modifications to the clustering/selection technique,  first tests of COSMO-HYBrid-EPS. Summary and plans

A.Montani; The COSMO-LEPS system. Main changes during the COSMO year (1) 30 November 2011, COSMO-LEPS “doubles”: a new ECMWF time-critical application was prepared and sent to ECMWF as for the implementation of COSMO-LEPS also at 00UTC (cleps00); cleps00 and cleps12 have identical configurations (use of COSMO-EU analysis fields also for cleps00 since 18 January 2012); cleps00 is potentially more exposed to product delays because of ECMWF system sessions (never happened so far). 29 March 2012, no more random choice of the convection scheme: following requests of DWD, members 1-8 use Tiedtke convection scheme, members 9-16 use Kain-Fritsch. 3 July 2012, system upgrades: COSMO model upgraded to perturbation tuning; generation of calibrated 24-h TP over Germany, Switzerland, Emilia-Romagna; archive of ECMWF-EPS model level fields at 0.25x0.25 on a large domain to enable reruns (last 3 months).

A.Montani; The COSMO-LEPS system. COSMO-LEPS ECMWF: present status d-1 dd+5 d+1d+2 d+4d+3 older EPS younger EPS clustering period Cluster Analysis and RM identification 4 variables Z U V Q 3 levels 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-Fritsch 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 v4.21 since July 2012; computer time (30 million BUs for 2012) provided by the ECMWF member states in COSMO. COSMO- LEPS Integration Domain

A.Montani; The COSMO-LEPS system. Outline Performance of the system:  time-series verification of COSMO-LEPS using SYNOP ;  case study assessment (“nevone 2012”).

A.Montani; The COSMO-LEPS system. –SYNOP on the GTS Time-series verification of COSMO-LEPS Main features: variable: 12h cumulated precip (18-06, UTC); period : from Dec 2002 to Jul 2012; 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, …, h, h; 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

A.Montani; The COSMO-LEPS system. Time series of ROC area  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 second part of 2011 for all but the highest threshold.  fc 30-42h: ROC area is low for the highest threshold for last winter; then recovery.  fc 78-90h: in the last months, some recovery of the score for the 15mm threshold, after a “difficult” beginning of the year.  Limited loss of predictability with increasing forecast range.

A.Montani; The COSMO-LEPS system. Heavy snowfalls in Emilia-Romagna (31/1 – 5/2/2012)

A.Montani; The COSMO-LEPS system. COSMO-I7 of 30/01/ UTC (+36-60h) h Snow observed (cm) over  the 24-hour period ending at 00UTC of 2/2/2012 forecasts (mm of equivalent water!)

A.Montani; The COSMO-LEPS system. COSMO-LEPS of 30/01/ UTC (+36-60h) available at UTC

A.Montani; The COSMO-LEPS system. COSMO-LEPS of 30/01/ UTC (+36-60h) COSMO-LEPS forecasts give early indication of possible heavy snowfall over the plain. COSMO-LEPS signal remained more stable and consistent than COSMO-I7.

A.Montani; The COSMO-LEPS system. Outline Present/future work:  modifications to the clustering/selection technique,  first tests of COSMO-HYBEPS.

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 do these distances grow with forecast range (in “COSMO- LEPS metric”)? Study a number of seasons.  Outcome: modifications to the number of clusters / number of global EPSs considered / clustering intervals.

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-HYBrid-EPS), where: a) 16 members comes from COSMO-LEPS, b) 1 member is nested on IFS (with Tiedtke scheme), c) 1 member is nested on IFS (with Kain-Fritsch scheme), d) 1 member is nested on GME, e) 1 member is nested on GFS. already existing 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.

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: –highest 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 of high-impact weather events for the snowfalls of February Other achievements: provision of ICs and BCs for convective-permitting ensembles; operational dissemination implemented for Romania; reorganisation of post-processing with Fieldextra.

A.Montani; The COSMO-LEPS system. Test modifications to the clustering methodology. Test COSMO-HYBrid-EPS. Increase vertical resolution? ensemble size?... tonight’s discussion. LAMEPS_BC project  consider possible modifications to COSMO-LEPS suite. COSMO-LEPS for TIGGE-LAM (GRIB2 encoding). COSMO-LEPS twice a day: generate probabilistic products from lagged ensembles. Future plans Support calibration and verification (  Versus?). Carry on collaboration within research project (HyMeX, EFAS, SAFEWIND, IMPRINTS, …).

A.Montani; The COSMO-LEPS system. Thank you !