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CONSENS Priority Project Status report COSMO year 2009/2010

CONSENS Priority Project Status report COSMO year 2009/2010. Involved scientists: Chiara Marsigli, Andrea Montani, Tiziana Paccagnella, Tommaso Diomede (ARPA-SIMC) Flora Gofa, Petroula Louka (HNMS) Andrea Corigliano (Uni BO), Michele Salmi (Uni FE). Overview.

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CONSENS Priority Project Status report COSMO year 2009/2010

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  1. CONSENS Priority ProjectStatus report COSMO year 2009/2010 Involved scientists: Chiara Marsigli, Andrea Montani, Tiziana Paccagnella, Tommaso Diomede (ARPA-SIMC) Flora Gofa, Petroula Louka (HNMS) Andrea Corigliano (Uni BO), Michele Salmi (Uni FE)

  2. Overview • Task 1: Running of the COSMO-SREPS suite • suite maintenance • implementation of the back-up suite • Task 2: Model perturbations • perturbation of physics parameters • perturbation of soil fields • Task 3: Ensemble merging • COSMO-LEPS – COSMO-SREPS comparison • Multi-clustering • Task 4: Calibration

  3. IFS (15km) – ECMWF global GME (30km) – DWD global UM – UKMO global GFS (50 km) – NCEP global COSMO-SREPS • INT2LM (v 1.14) • COSMO (v 4.12) • 00 UTC and12 UTC • 7 km • 40 levels • 16 members • 48 h • 16 physics perturbations

  4. T1 - Running of the COSMO-SREPS suite(C. Marsigli) • Maintenance of the COSMO-SREPS suite at ECMWF • Implementation of the back-up suite: • The work involves also DWD (even if implicitly!) • A BC suite is being implemented by DWD at ECMWF, to provide BCs to COSMO-DE-EPS • The BC suite will provide the 4 control members to COSMO-SREPS • Direct nesting on the global models • Domain enlargement and resolution increase (7 km) • 12 members are currently run every day (IFS, GME, GFS branches)

  5. Suite set-up convection scheme: 0 Tiedtke 1 Kain-Fritsch ratio of laminar scaling factors for heat over sea minimal stomata resistance maximal turbulent length scale length scale of thermal surface patterns scaling factor of the laminar layer depth

  6. The new COSMO-SREPS suite – first results • Direct nesting of COSMO at 10 km (!) on IFS (15km) and GME (30 km) • Analysis for MAM 2010 (76 dates, suite running from mid March) • Scores computed for: • total precipitation • 2m temperature and dew-point temperature

  7. MAM10 K K 1.0 3.0 0.5 2.5 0.0 -0.5 2.0 -1.0 -1.5 1.5 -2.0 gme 2m T – deterministic scores BIAS MAE ifs Northern Italy data - Nearest grid point

  8. MAM10 K K 1.0 3.0 0.5 2.5 0.0 -0.5 2.0 -1.0 -1.5 1.5 -2.0 tur_len < pat_len > rlam_heat < rat_sea < tur_len > pat_len > rlam_heat < rat_sea < 2m T – deterministic scores BIAS MAE crsmin > Northern Italy data - Nearest grid point

  9. MAM10 K K 3.0 1.5 1.0 2.5 0.5 2.0 0.0 1.5 -0.5 1.0 -1.0 gme 2m Td – deterministic scores BIAS MAE ifs Northern Italy data - Nearest grid point

  10. MAM10 K K 3.0 1.5 1.0 2.5 0.5 2.0 0.0 1.5 -0.5 1.0 -1.0 tur_len < pat_len > rlam_heat < rat_sea < tur_len > pat_len > rlam_heat < rat_sea < 2m Td – deterministic scores BIAS MAE crsmin > Northern Italy data - Nearest grid point

  11. MAM10 24h precipitation 0-24h BSS • Northern Italy network • Average over 0.5 x 0.5 deg boxes ROC

  12. Remarks for COSMO-SREPS • IFS and GME driven runs are of similar quality in terms of t and td, but have different BIAS (especially for td) • For precipitation forecasts, a “well-mixed” 4 members ensemble is as skilful as the full 8 member ensemble, even in the members are of different quality • The runs with physics perturbations have similar scores, the main differences are in td

  13. T2.1 - Model perturbations: parameters(F. Gofa, P. Louka, C. Marsigli) • New parameter perturbations are tested in a dedicated test suite (CSPERT), where IC and BCs are not perturbed (IFS operational run) • BUs are provided from Italian Special Projects • New runs of the CSPERT suite were performed, from Spring 2009 to Spring 2010 • Analysis of the results for MAM and SON 2009

  14. MAM09 6h precipitation – Northern Italy tp > 1mm /6h tp > 10mm /6h

  15. MAM09 T and Td – Greece

  16. SON09 6h precipitation – Northern Italy tp > 1mm /6h tp > 10mm /6h

  17. Remarks from the CSPERT suite • Mu_rain=0: • Less precipitation for low threshold • Improve the high thresholds, especially Tiedtke member • Cloud_num=5e+07: • No strong impact • Pat_len=10000: • Increase the precipitation, especially Tiedtke member • Little POD improvement with small effect on FA • the set crsmin=200 (largest) and rat_sea=1 (smallest) seems to “improve” bias for T and Td, (over Greece)

  18. 2.2 Model perturbations: Developing perturbations for the lower boundary(F.Gofa, P.Louka) Aim Implement a technique for perturbing soil moisture conditions and explore its impacts Reasoning The lack of spread is typically worse near the surface rather than higher in the troposphere. Also, soil moisture is of primary importance in determining the partition of energy between surface heat fluxes, thus affecting surface temperature forecasts

  19. T3.1 - Ensemble merging: comparison of the methodologies(C. Marsigli) • COSMO-LEPS (EPS downscaling + physics perturbations) and COSMO-SREPS (multi-model IC and BCs + physics perturbations) are compared: • 12UTC runs, over SON 2009 (34 runs, 12 members each) • During the last year of the project, a more clean comparison has been scheduled: • 16 runs of both systems available every day • same model version • same namelists • same perturbations of the physics parameters

  20. +24h med05

  21. +48h med05

  22. initial conditions by EPS initial conditions by MOGREPS T3.2 - Ensemble merging: development of the COSMO-LEPS clustering(A. Montani, A. Corigliano) • Aim: perform a dynamical downscaling where driving members for COSMO are taken from more than one global ensemble • ECMWF EPS and UKMO MOGREPS have been considered • The cluster analysis is applied on different sets of members coming from the global ensembles

  23. Issues • How does the spread/skill relationship of the single-model and mixed global ensembles look like? • Where do the best (and the worst) elements of the reduced ensembles come from? How to they score depending on their “origin”? • What is the impact of the ensemble reduction? • Is it worth weighting according to the cluster population? • The following ensembles are considered: • EPS (50+1): 51 members • MOGREPS (23+1): 24 members • MINI-MIX (EPS24 + MOGREPS24): 48 members • MEGA-MIX (EPS51 +MOGREPS24): 75 members

  24. Performance of models: spread-skill relation MEGAMIX 75 MOGREPS 24

  25. Where do the best (and the worst) elements come from? MINIMIX RM MEMBER Percentage and RMSE best worst best worst

  26. Impact of RM weighting MEGAMIX 75: RMSE_EM = 30.7 m REDU-MEGAMIX: RMSE_EM = 32.4 m REDU-MEGAMIX weighted: RMSE_EM_W = 31.8 m

  27. Future plans • Continue the work outside the CONSENS project (since no programming of the work is possible at this stage) • Implement dynamical downscaling: nest COSMO model in the selected RMs and generate “hybrid” COSMO-LEPS using boundaries from members of different global ensembles. • For a number of case, compare operational COSMO-LEPS and “hybrid” COSMO-LEPS.

  28. T4 - Calibration(T. Diomede) • Data collection: • Data over Switzerland, provided by MeteoSwiss (interpolated with the SYMAP method on the 417 COSMO-LEPS grid points covering Switzerland; more than 450 stations, originally) • Data over Germany, provided by DWD (1038 stations, interpolated with an inverse-squared-distance weighting method over the 3566 Germany grid points) • calibration over Switzerland and Germany, also on sub-areas • test on the use of the specific humidity at 700 hPa for performing the analog search • test on the application of calibration functions which are specific for underestimation and overestimation model conditions over ER; • comparison among results obtained for different lengths of the reforecast dataset over Switzerland and Emilia-Romagna; • verification of the calibration process by the coupling of QPFs with an hydrologic model (implemented for the Reno river basin, Emilia-Romagna).

  29. autumn 80th percentile Calibration over Germany +18-42h +66-90h

  30. summer 80th percentile Calibration over Germany +18-42h +66-90h

  31. +66-90h 95th percentile Calibration over Germany autumn summer

  32. summer 80th percentile Calibration over Switzerland lead time: +18-42 h lead time: +66-90 h

  33. autumn 80th percentile Calibration over Switzerland lead time: +18-42 h lead time: +66-90 h

  34. Differences among COSMO regions 80th percentile 95th percentile autumn summer

  35. Impact of using a reduced reforecast data-set +20-44h +68-92h autumn summer

  36. calibration specific for over- and under-estimation autumn winter summer • using a predictor to identify if the current forecast will fall in the underestimation or in the overestimation category • the forecast of a certain field compared against to the best analog of the same field, which identify the category 95th percentile

  37. autumn Impact on hydrological predictions 95th percentile 90th percentile missed false alarms

  38. Remarks and plans • The performance of the calibration methodologies are very much dependent on the geographic area • A multi-variable approach based on the evaluation of upper air fields at different pressure levels and times of the day will be tested • Calibration could be done over all COSMO countries included in the domain (Greece, Italy, Poland, Romania), if dense and long precipitation data series are available

  39. Final Remarks

  40. Next milestones • the back-up suite has been implemented, with 12 members. During next season, it will move to 16 members, probably using only the 3 global models fully available (IFS, GME, GFS) • the new microphysics perturbations will be added to the suites during within autumn 2010 • test the soil moisture perturbation technique in the COSMO-SREPS suite over a period (two seasons)

  41. Next milestones • Carry on the intercomparison between COSMO-LEPS and COSMO-SREPS for a period (from now to February 2011): • 16 runs of both systems available every day • same model version • same namelists • same perturbations of the physics parameters • EPS now having EnDA+SVs • Decide about the implementation of the calibration of COSMO-LEPS outputs

  42. Hints for discussion • COSMO-SREPS: • Problems with the UM boundary conditions • Use of 3 sets of global models only (but still 16 members) • Which are the needs for BCs to run convective-permitting ensembles in the COSMO countries? • Calibration: • The performance of the calibration methodology is dependent on the precipitation threshold and on the considered area => different calibration methods for different areas? • Difficulty in “catching the bias” of precipitation over Emilia-Romagna, dependent on weather type

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