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A two-moment microphysical scheme for mesoscale and microscale cloud resolving models

A two-moment microphysical scheme for mesoscale and microscale cloud resolving models. Axel Seifert National Center for Atmospheric Research. Motivation. Aerosol-Cloud interactions can be a strong feedback in the climate system

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A two-moment microphysical scheme for mesoscale and microscale cloud resolving models

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  1. A two-moment microphysical scheme for mesoscale and microscale cloud resolving models Axel Seifert National Center for Atmospheric Research

  2. Motivation • Aerosol-Cloud interactions can be a strong feedback in the climate system • Quantitative precipitation forecasts suffer from oversimplified microphysical models • Many ongoing projects on weather modification, but little scientific knowledge •  improved microphysical models are necessary

  3. Microphysical models: x = particle mass

  4. Generalized Gamma Distribution x = particle mass,  = shape parameter,  = tail parameter D inm D inm

  5. A two-moment warm phase scheme Use mass and number concentrations to getan explicit size information 4 Variables (Seifert and Beheng 2001, Atmos. Res.)

  6. A two-moment mixed-phase cloud scheme

  7. A two-moment mixed-phase cloud scheme

  8. What happend so far .... • Comparison with bin microphysics • Sensitivity study showed that especially high CAPE, low wind shear convective systems are sensitive to aerosols/CCN • Simulation of isolated observed thunderstorms • Severe storms during BAMEX • WRF, MM5 and LM implementation

  9. Comparison within HUCM

  10. Comparison within HUCM

  11. Timeseries of maximum mass concentrations BIN BULK CONT MARI

  12. Total grid averaged precipitation

  13. CCN effects on different storm types • Weisman and Klemp (1982) • sensitivity study, but nowincluding CCN as a third external parameter: • Variation of • 1. CAPE 2. vertical wind shear3. CCN concentration • Effects on total precipitation? (Seifert and Beheng 2003, submitted)

  14. Total 3h-precipitation multicell conv. supercell convection

  15. Total 3h-precipitationand rel. change for cont. CCN

  16. WRF simulation of a CRYSTAL-FACE storm (100x80 km, 250 m resolution, warm bubble, single sounding)

  17. Observations vs. WRF simulationX-band reflectivity

  18. Observations vs. WRF simulationW-band reflectivity

  19. Attenuation by liquid water

  20. Real-time WRF 4 km BAMEX Forecast Valid 6/10/03 12Z 4 km BAMEX forecast 36 h Reflectivity 4 km BAMEX forecast 12 h Reflectivity Composite NEXRAD Radar

  21. BAMEX 10 June 00 UTC + 09h Column max. reflectivity (WRF) WRF’s Lin-type scheme Reisner-Thompson scheme Seifert-Beheng scheme

  22. BAMEX 10 June 00 UTC + 23h Column max. reflectivity (WRF) WRF’s Lin-type scheme Reisner-Thompson scheme Seifert-Beheng scheme

  23. BAMEX 10 June 00 UTC + 23h Accumulated precip during 23 h WRF’s Lin-type scheme Reisner-Thompson scheme Seifert-Beheng scheme

  24. Acknowledgements: Klaus D. Beheng, Karlsruhe Uli Blahak, Karlsruhe Michael Baldauf, Karlsruhe Jochen Förstner, Karlsruhe Alexander Khain, Jerusalem Andrei Pokrovsky, Jerusalem Bill Hall, NCAR Andy Heymsfield, NCAR Morris Weisman, NCAR Gerry Heymsfield, NASA Scientific Computing Centers at Karlsruhe and NCAR

  25. Various one- and two-moment schemes

  26. BAMEX 10 June 00 UTC + 19h Column max. reflectivity (WRF) WRF’s Lin-type scheme Reisner-Thompson scheme Seifert-Beheng scheme

  27. Maximum vertical velocities (HUCM)

  28. Coupling of microphysics and dynamics!

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