1. 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.

2. 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.

3. 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
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.

4. A.Montani; The COSMO-LEPS system.
Outline
Recent upgrades of COSMO-LEPS:
A.Montani; The COSMO-LEPS system.

5. 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 ML fields at 0.25x0.25 on a large domain to enable reruns (last 3 months).
A.Montani; The COSMO-LEPS system.

6. 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.

7. 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.

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

9. 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

10. 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

11. 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.

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

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

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

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

16. 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.

17. 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.

18. 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.

19. 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.

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

21. 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.

22. 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.

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