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Experiments on COSMO snow parameterization

Experiments on COSMO snow parameterization. J. Helmert, E. Machulskaya, B. Ritter with support of H. Ruppert, J. Förstner, Th. Hanisch. Background. COSMO experiments motivated from GME changes on - snow albedo - snow cover fraction - snow albedo evolution

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Experiments on COSMO snow parameterization

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  1. Experiments on COSMOsnow parameterization J. Helmert, E. Machulskaya, B. Ritter with support of H. Ruppert, J. Förstner, Th. Hanisch

  2. Background COSMO experiments motivated from GME changes on - snow albedo - snow cover fraction - snow albedo evolution Aim: consistent physics in NWP models decrease of cold bias in T_2M during winter COSMO experiments: 8050: 18.12.2010 – 02.03.2011 snow fraction 8232: 18.02.2011 – 17.04.2011 snow albedo evolution 8233: 18.02.2011 – 17.04.2011 snow albedo evolution + snow fraction

  3. Snow albedo Csalb_snow_min = 0.4000.500 ! snow for forest free surfaces Csalb_snow_max = 0.7000.850 ! snow for forest free surfaces Csalb_snow_fe = 0.2000.270 ! snow with evergreen forest Csalb_snow_fd = 0.2000.320 ! snow with deciduous forest Dutra et al., 2010

  4. Snow aging Temporal evolution ofsnow albedo New approach Aging function S

  5. Snow fraction Wcr = 15mm ROUTI Hcr = 0.1m EXP Dutra et al., 2010

  6. Snow Fraction ROUTI GME

  7. Snow Fraction EXP GME

  8. Snow Fraction ROUTI COSMO

  9. Snow Fraction EXP COSMO

  10. SYNOP VERIF EXP 8050 vs ROUTI 18.12.10-30.01.11, 00 UTC BIAS T2M TD2MD TMIN TMAX PS DD FF VW RMSE T2M TD2MD TMIN TMAX PS DD FF VW

  11. SYNOP VERIF EXP 8050 vs ROUTI 31.01.11-28.02.11, 00 UTC BIAS T2M TD2MD TMIN TMAX PS DD FF VW RMSE T2M TD2MD TMIN TMAX PS DD FF VW

  12. Snow melting 2011032112

  13. Snow melting 2011032112

  14. Snow melting 2011032112

  15. Snow melting 2011032112

  16. Snow melting 2011032112

  17. SYNOP VERIF EXP 8032 vs ROUTI 18.03.11-17.04.11, 00 UTC BIAS T2M TD2MD TMIN TMAX PS DD FF VW RMSE T2M TD2MD TMIN TMAX PS DD FF VW

  18. SYNOP VERIF EXP 8033 vs ROUTI 18.03.11-17.04.11, 00 UTC BIAS T2M TD2MD TMIN TMAX PS DD FF VW RMSE T2M TD2MD TMIN TMAX PS DD FF VW

  19. Summary • COSMO experiments showed the expected impact of snow • parameterization changes on total albedo and T_2M • Parameterization changes are independent of used snow • model (single layer, multilayer) • Results should be used also in future COSMO with TILE • Further routine accompanying experiments (single layer, • multi layer) intended for autum 2011 • Aim: Routine change in Spring 2012

  20. SYNOP VERIF EXP 8050 vs ROUTI RANGE 1, 12 UTC, BIAS

  21. SYNOP VERIF EXP 8050 vs ROUTI RANGE 1, 12 UTC, RMSE

  22. SYNOP VERIF EXP 8050 vs ROUTI RANGE 2, 12 UTC, BIAS

  23. SYNOP VERIF EXP 8050 vs ROUTI RANGE 2, 12 UTC, RMSE

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