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, 10-13 September 2012 A.Montani; The COSMO-LEPS system.

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-HYBEPS... Summary and plans A.Montani; The COSMO-LEPS system.

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

A.Montani; The COSMO-LEPS system. Outline Recent upgrades of COSMO-LEPS: 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 4.21 + perturbation tuning; generation of calibrated 24-h TP over Germany, Switzerland, Emilia-Romagna; archive of ECMWF-EPS ML fields at 0.25x0.25 on a large domain to enable reruns (last 3 months). A.Montani; The COSMO-LEPS system.

Activity for COSMO countries / research projects 16 February 2012: reorganisation of dissemination to ARPA-SIMC; 30 May 2012: operational dissemination implemented for Romania; 1 July 2012: reorganisation of post-processing with Fieldextra; 13 July 2012: new dissemination implemented for DWD. 5 September 2012: dissemination (both model and graphical output) for HYMEX campaign. A.Montani; The COSMO-LEPS system.

A.Montani; The COSMO-LEPS system. Outline Performance of the system: time-series verification of COSMO-LEPS using SYNOP; A.Montani; The COSMO-LEPS system.

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

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. In some seasons of 2011/2012, few events with heavy precipitation: possible limited significance of the results for the 15mm threshold. fc 30-42h: ROC area is low for the highest threshold for last winter; then recovery. fc 78-90h: in the last months, 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. 11

Seasonal scores of ROC area: the last 3 autumns 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. Valuable forecast systems have ROC area values > 0.6. Need to take into account the different statistics for each season (SON 2011 was the driest). Best performance for the autumn 2011, for all forecast ranges and low/mid thresholds. Similar results for longer forecast ranges (not shown). A.Montani; The COSMO-LEPS system. 12

Ranked Probability Skill Score: time series + seasonal scores (MAM) A sort of BSS “cumulated” over all thresholds. RPSS is written as 1-RPS/RPSref. 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. A.Montani; The COSMO-LEPS system.

A.Montani; The COSMO-LEPS system. Outline Performance of the system: case study assessment (“nevone 2012”). A.Montani; The COSMO-LEPS system.

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

A.Montani; The COSMO-LEPS system. COSMO-I7 of 30/01/2012 12UTC (+36-60h) +36-60h available at 17.30 UTC Snow observed (cm) over  the 24-hour period ending at 00UTC of 2/2/2012 A.Montani; The COSMO-LEPS system.

COSMO-LEPS of 30/01/2012 12UTC (+36-60h) A.Montani; The COSMO-LEPS system. available at 23.30 UTC

COSMO-LEPS of 30/01/2012 12UTC (+36-60h) COSMO-LEPS more stable and consistent than COSMO-I7 in the prediction of heavy snowfall over the plain. A.Montani; The COSMO-LEPS system.

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 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. 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: 16 members comes from COSMO-LEPS, 1 member is nested on IFS (uses Tiedtke scheme), 1 member is nested on IFS (uses Kain-Fritsch scheme), 1 member is nested on GME, 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 A.Montani; The COSMO-LEPS system.

A.Montani; The COSMO-LEPS system. Outline Summary and plans. A.Montani; The COSMO-LEPS system.

Time-series verification Case-study verification 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. A.Montani; The COSMO-LEPS system.

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

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