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COSMO-RU ensemble weather forecasting system: first steps

COSMO-RU ensemble weather forecasting system: first steps. Dmitry Alferov, Elena Astakhova, Gdaly Rivin, Inna Rozinkina Hydrometcenter of Russia 13-th COSMO General Meeting, Rome, 5-9 September 2011. Contents. Global medium-range EPS at the Hydrometcenter of Russia

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COSMO-RU ensemble weather forecasting system: first steps

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  1. COSMO-RU ensemble weather forecasting system: first steps Dmitry Alferov,Elena Astakhova, Gdaly Rivin, Inna Rozinkina Hydrometcenter of Russia 13-th COSMO General Meeting, Rome, 5-9 September 2011

  2. Contents • Global medium-range EPS at the Hydrometcenter of Russia • COSMO-RU EPS description • COSMO-RU EPS products • Case study: freezing rain in Moscow • COSMO-RU EPS verification • Prospects

  3. Global medium-range EPS at the Hydrometcenter of Russia SLAV-2008 model : Semi-Lagrangian vorticity-divergence dynamical core, ALADIN/LACE parameterizations,0.9x0.72 degrees lon/lat (~70 km), 28 levels

  4. Global EPS products • Spaghetti (T850, pmsl, H500) • Ensemble meteograms (T2m, prec, T850, total clouds, middle clouds, pmsl) • Mean+spread (H500, T850) • Plumes(T850, T2m, 6h prec) • Postage stamps (T2m, prec) • Probability maps (24-h prec, 6-h prec, wind 10m, wind 850 hPa, T850 anom, H500 anom, pmsl anom) Thresholds from the Guideline of the Lead center on Verification of Ensemble Prediction Systems

  5. Since October 2010: Verification results for precipitation are published on the Web site of the Lead Centre on Verification of Ensemble Prediction Systems http://epsv.kishou.go.jp/EPSv/html/rumseps/probdiagrams.html

  6. Contents • Global medium-range EPS at the Hydrometcenter of Russia • COSMO-RU EPS description • COSMO-RU EPS products • Case study: freezing rain in Moscow • COSMO-RU EPS verification • Prospects

  7. COSMO-RU EPS DESCRIPTION: main features Murmansk • 28 members • Different variants of model physics, numerical schemes for model dynamics and boundary conditions schemes • Ensemble members: COSMO-RU model, grid: 350×310×40, Δx=Δy=14 km • Control experiment:COSMO-RU model, Δx=Δy=7 km • Forecast length:78 hours • Computer:SGI Altix 4700 Itanium 2, 1.66 GHz, NUMALink, 1664 PEs, Peak 11 Tflops • Performance: 256 CPUs, forecast ready in 7 hours • 1 run / day at 00 UTC Omsk Moscow Offenbach Rome Sochi Athens The model integration domain

  8. COSMO-RU EPS DESCRIPTION: applied perturbations

  9. Contents • Global medium-range EPS at the Hydrometcenter of Russia • COSMO-RU EPS description • COSMO-RU EPS products • Case study: freezing rain in Moscow • COSMO-RU EPS verification • Prospects

  10. COSMO-RU EPS PRODUCTS:probability forecasts(6 h accumulated precipitation) Moscow Probability of precipitation > 0.25 mm / 6 h Initial time: 00 UTC 30.05.2010, forecast valid at 06 UTC 2.06.2010

  11. COSMO-RU EPS PRODUCTS: spaghetti plots (T2m)25˚C isotherm spaghetti, 31 July 2010 + 78 hours (blocking case with extreme heat) Thick black line – actual data; Thick red line – nonperturbed control 78-hour forecast; Thick blue line – ensemble mean; Thin coloured lines – ensemble members.

  12. COSMO-RU EPS PRODUCTS: spaghetti plots (T2m)25˚C isotherm spaghetti, 31 July 2010 + 78 hours (blocking case with extreme heat) Thick black line – actual data; Thick red line – nonperturbed control 78-hour forecast; Thick blue line – ensemble mean; Thin coloured lines – ensemble members. Large instability in the Urals region Ensemble mean forecast shows much better skill (and some members too)

  13. Contents • Global medium-range EPS at the Hydrometcenter of Russia • COSMO-RU EPS description • COSMO-RU EPS products • Case study: freezing rain in Moscow • COSMO-RU EPS verification • Prospects

  14. CASE STUDY: freezing rain in Moscow • Intense freezing rain in Moscow region on 25-26 December 2010 caused damage of trees, electric lines and constructions due to large mass of glazing ice formed during this time. • Transport problems and closing of airports followed.

  15. CASE STUDY: freezing rain in Moscow Wind Temp, C PMSL, hPa mm/3h Prec mm/h Clouds Conv clouds, m

  16. CASE STUDY: freezing rain in Moscow Wind Temp, C PMSL, hPa Combined rain and snow mm/3h Prec mm/h Clouds Conv clouds, m

  17. CASE STUDY: freezing rain in Moscow Wind Temp, C PMSL, hPa Temperature inversion near 0˚C mm/3h Prec mm/h Clouds Conv clouds, m

  18. CASE STUDY: freezing rain in MoscowCOSMO-RU 18-hour control forecast (grid size 7 km) PMSL, clouds, precipitation PMSL, T2m, H500 • Left scale – clouds; • Right scale – precipitation; • Isolines – PMSL; • Initial time: 12 UTC 25.12.2010; • Forecast valid at 06 UTC 26.12.2010 • Color scale – T2m; • Brown isolines – H500; • White isolines – PMSL; • Initial time: 12 UTC 25.12.2010; • Forecast valid at 06 UTC 26.12.2010

  19. CASE STUDY: freezing rain in Moscow Temperature, cross-section along the latitude of Moscow (55.786˚ N) 0˚C isotherm ‘spaghetti’ plot 66-hour COSMO-RU ensemble forecast Analysis for COSMO-RU/14 model -4˚C Pressure, hPa Pressure, hPa 0˚C 0˚C -4˚C 0˚C Longitude Longitude • Initial time: 12 UTC 23.12.2010 • Forecast valid at 06 UTC 26.12.2010 Longitude of Moscow (37.557˚ E)

  20. CASE STUDY: freezing rain in Moscow Temperature, cross-section along the latitude of Moscow (55.786˚ N) 0˚C isotherm ‘spaghetti’ plot 66-hour COSMO-RU ensemble forecast Analysis for COSMO-RU/14 model -4˚C Pressure, hPa Pressure, hPa 0˚C 0˚C -4˚C 0˚C Longitude Longitude • Initial time: 12 UTC 23.12.2010 • Forecast valid at 06 UTC 26.12.2010 Longitude of Moscow (37.557˚ E) Temperature inversion near 0˚C successfully forecasted with high probability Ensemble members with pat_len = 10000 m gave the worst forecasts at all lead times

  21. Contents • Global medium-range EPS at the Hydrometcenter of Russia • COSMO-RU EPS description • COSMO-RU EPS products • Case study: freezing rain in Moscow • COSMO-RU EPS verification • Prospects

  22. COSMO-RU EPS VERIFICATIONReliability diagrams T2m > 30˚C July-August 2010 T2m < -20˚C December 2010 – January 2011 Observed relative frequency Observed relative frequency Perfect forecast Perfect forecast No skill (reliability = resolution) No skill (reliability = resolution) No resolution (climatology) No resolution (climatology) Forecast probability Forecast probability Reliability diagrams show the quality of probability forecast. These diagrams show very good forecasts, almost perfect in summer 2010 and a bit worse in winter 2010.

  23. Contents • Global medium-range EPS at the Hydrometcenter of Russia • COSMO-RU EPS description • COSMO-RU EPS products • Case study: freezing rain in Moscow • COSMO-RU EPS verification • Prospects

  24. Prospects • Regular ensemble runs • A comprehensive study of the effect of different perturbations, better choice of parameter values • Reduction of the number of ensemble members for higher performance • Analysis of EPS skill in probabilistic forecasting of various weather elements (wind, H500, etc.) • High-resolution (2.2 km) ensemble for Sochi region

  25. Thank you!

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