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Ensemble activites and plans at MeteoSwiss

Ensemble activites and plans at MeteoSwiss. COSMO-GM, Rome, 5-9 September 2011. André Walser MeteoSwiss. Overview. Today: regional ensemble forecasts fully based on COSMO-LEPS. Forecast suite @ ECMWF managed by ARPA-SIMC (time critical application). Reforecast suite @ ECMWF

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Ensemble activites and plans at MeteoSwiss

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  1. Ensemble activites and plans at MeteoSwiss COSMO-GM, Rome, 5-9 September 2011 André Walser MeteoSwiss

  2. Overview • Today: regional ensemble forecasts fully basedon COSMO-LEPS Forecast suite @ ECMWF managed by ARPA-SIMC (time critical application) Reforecast suite @ ECMWF managed by MeteoSwiss DMO DMO Product generation & verification @ Swiss HPC center (CSCS) • Future: Development of COSMO-E

  3. COSMO-LEPS clients and products Internal and ~20 external customers

  4. Last year’s cloud cover problem… Low-level cloud cover (CLCL) ~50% of members produced low-level clouds

  5. SYNOP verif T_2M CH JJA2010 lead-time +(25-48)h ~2K Observations COSMO-LEPS ensemble mean COSMO-7 00 UTC 00 UTC

  6. Last year‘s conclusion • Cloud problem in COSMO-LEPS caused by Kain-Fritsch convection scheme together with a too moist boundary layer  COSMO-EU soil merge should be introduced as soon as possible

  7. Soil merge implementation • Merge is operational since 11/04/2011 12 UTC forecast: • fresh snow (FRESHSNW) • snow density (RHO_SNOW) • interception water (W_I) • snow temperature (T_SNOW) • snow water equivalent (W_SNOW) • soil temperature (T_SO) • soil moisture (W_SO) • soil ice (W_ICE) • Large impact on verification results for ensemble mean (following slides)

  8. SYNOP verif T_2M CH JJA2011 lead-time +(25-48)h Observations COSMO-LEPS ensemble mean COSMO-7 00 UTC 00 UTC

  9. SYNOP verif T_2M Europe JJA2011 STDE Bias COSMO-LEPS ensemble mean outperforms COSMO-7 for all lead-times

  10. SYNOP verif TD_2M Europe JJA2011 STDE Bias COSMO-LEPS ensemble mean outperforms COSMO-7 for all lead-times

  11. SYNOP verif CLCT Europe JJA2011 STDE Bias COSMO-LEPS ensemble mean outperforms COSMO-7 for all lead-times

  12. Soil merge: Impact on snow cover old suite 10.4.2011 New suite 11.4.2011 Snow height merged from COSMO-EU Snow height interpolated from IFS  Large improvement due to higher resolution of snow analysis

  13. COSMO-LEPS «wish list» • Continue soil merge as long as COSMO-EU is in operation (up to 2014?) • Keep COSMO model configuration close to COSMO-EU • Implementation of 00 UTC forecast as soon as possible • Use of „Super-Ensemble strategy“ for clustering still appropriate? • Soil moisture perturbation

  14. 1989-01-01 1989-01-03 1989-01-06 LT: 90h Status COSMO-LEPS reforecast suite Intention: statistically independent data set for a long period: • reforecasts over a period of 20 years (1989-2008) • every 3rd day with 90h lead time (~1 month in advance) • same model version and configuration as COSMO-LEPS suite • ERA-interim reanalysis as initial and boundary fields • New: To account for COSMO-EU soil merge, a soil moisture bias correction is applied, based on a comparison of COSMO-EU and interpolated ERA-interim for 2008) • Available at ECMWF mars archive retrieve, time=12:00:00, date=2011-08-11, stream=enfh, step=0/to/90, levtype=sfc, expver=1, type=cf, hdate=1989-08-11/to/2008-08-11 class=co, param=61.2

  15. Fieldextra news: Ensemble quantiles • Fieldextra v10.4 allows to calculate user-defined quantiles, e.g.:&Process out_field = "TOT_PREC", product_category = 'eps_quantile', quantile = 75. / • Simple algorithm (thanks to S. Theis for the input!): • Q0 = ensemble min • Q100 = ensemble max • linear interpolation between two members

  16. q(m3)=10 q(m2)=30 q(m1)=50 q(m5)=70 q(m4)=90 m2 m1 m3 m5 m4 Q20 Q40 * * * y(mx) * * * Q25 Fieldextra news: Ensemble quantiles • Example: 5 member ensemble, equally weighted, calculate 25% quantile • Sort members • Calculate q values for each members (according to weights) • Interpolate between members

  17. Development of COSMO-E

  18. Expectations of our clients • Focus on Alpine region / Alpine specific problems • Consistency of products through different lead times and scales • High availability of products • Two broad classes of products: • Very high resolution in space and time, typically 24 hours, rapid update cycle  COSMO-1 • Regionalprobabilistic forecasts up to 3-5 days  COSMO-E

  19. Boundary conditions for MeteoSwiss • Human resources • Limited: MeteoSwiss internal project COSMO-NExT (Novel Expert Tools) with no additional resources • COSMO priority projects • Collaboration with partners • Computing resources • National HPC strategy with funding for MeteoSwiss • HP2C project for code adaptation to new architectures

  20. Regional probabilistic forecasts: COSMO-E VarEPS: Boundary conditions forecasts twice per day, ~3 km grid size, 60 levels

  21. COSMO-E setup Implementation of Perturbations: initial conditions boundary conditions model physics LETKF with 40 members, PP KENDA COSMO-DE-EPS & PP CONSENS ECMWF BC project MeteoSwiss resources 21 ensemble members:final configuration depends on performance of COSMO code on our 2015 HPC system  HP2C project / PP POMPA

  22. 12 15 18 21 00 03 06 09 12 15 18 .. +5d COSMO-E setup (2) Valid Time (UTC) Assimilation (LETKF, hourly update) Forecasts .. +5d .. +5d • forecast start ~75 min after analysis time (after COSMO-1) • elapsed time ~45 min

  23. Time-table 2012 2013 2014 2015 Operational COSMO-LEPS LETKF Tests Regular EPS runs Preopera-tional Opera-tional COSMO-E Setup LETKF setup physics & BC perturbations Verification & final tuning

  24. Thank you !

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