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Intercomparison and Evaluation of Single-Column Models for GABLS3: Preliminary Results

This paper discusses the preliminary results of the intercomparison and evaluation of single-column models for the GABLS (GEWEX Atmospheric Boundary Layer Study) 3 experiment. The study compares the models' performance in simulating atmospheric processes and boundary layer characteristics using observational data from the Cabauw site. The results highlight the strengths and differences among the models and provide insights for further analysis.

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Intercomparison and Evaluation of Single-Column Models for GABLS3: Preliminary Results

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  1. INTERCOMPARISON AND EVALUATION OF SINGLE-COLUMN MODELSFOR GABLS3: PRELIMINARY RESULTSFred Bosveld, Peter Baas, Cisco de Bruijn and Bert Holtslag. With contributions of: Wayne Angevine (NOAA) Sunkanta Basu (TTU) Eric Bazile (MeteoFrance) John Edward (MetOffice) Michael Ek (NCEP Jocelyn Mailhot (Env Can) Jon Pleim (NOAA) Matthias Raschendorfer (DWD) Gert-Jan Steeneveld. (WUR) 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  2. INTERCOMPARISON AND EVALUATION OF SINGLE-COLUMN MODELSFOR GABLS3: PRELIMINARY RESULTSFred Bosveld, Peter Baas, Cisco de Bruijn and Bert Holtslag. Content: Background Case selection Case set-up Results 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  3. Context 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  4. The Cabauw Site 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  5. Case Selection • 7-year database (2001-2006) • Geostrophic wind • Net radiation • Subset of clear night with relatively constant Vgeo • Relatively constant Ta200 • No fog formation • Dewpoint depression • Development low-level jet • 9 Suitable cases remained. Used to identify generic features. • No sudden jumps in time series of e.g. dew point • No small scale synoptic features (e.g. sea-breeze) • GABLS3 case, 1 – 2 July 2006 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  6. GABLS3 Example generic features Wind speed 200 m for 9 selected nights Vgeo 12 18 0 6 12 Hours 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  7. GABLS3 Example generic features Potential temperature difference between 200 and 2 m for 9 selected nights 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  8. The new GABLS case: synoptic situation 2 July 2006, 0 UTC 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  9. Profiler wind vectors 1000 800 600 400 200 0 Height (m) 12 14 16 18 20 22 0 2 4 6 8 10 12 TimeUTC Some observations: the low-level jet 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  10. SCM case set-up Simulation period • 1-2 July 2006, 12 – 12 UTC (24 h) To do • Initial Conditions • Soil / vegatation specifications • Atmospheric forcings. Tools • 12 hourly soundings from De Bilt • Observations from the site • Various 3D models 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  11. Atmospheric humidity, initialization GABLS3 1 W W 2 3 D D 1 2 3 Observed q at 200 m, July 1st, 2006 Soundings De Bilt 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  12. What about soil moisture? Tuning parameter to get correct sensible and latent heat fluxes at start of simulation ( b = 0.33). sensitivity runs for soil moisture with RACMO 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  13. 12 18 24 6 12 Time (UTC) Derivation of atmospheric forcing Geostrophic forcing Advective tendencies obs vg fit obs ug fit 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  14. Exampe: influence advection on SCM runs 8th EMS/7th ECAC, Amsterdam, 29 Sep – 3 Oct 2008

  15. Models. 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  16. Observations. Tower profiles of wind, temperature and humidity Winprofiler/RASS profiles of wind and (sonical) temperature Radio sounding De Bilt (25 km) from Cabauw BSRN incoming radiation Land surface field outgoing radiation and surface fluxes 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  17. Surface fluxes 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  18. Surface fluxes 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  19. Surface fluxes 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  20. Surface fluxes 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  21. Profiles ● ● 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  22. Profiles ● ● 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  23. Profiles ● ● 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  24. Surface parameters 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  25. Surface parameters 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  26. 200m level 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  27. Surface parameter 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  28. Low level jet 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  29. Conclusions • Long time series at Cabauw enables the selection of a reasonable ideal case • Carefully prescribing the forcings on the vertical column enables a meaningfull comparison between models and observations • Together with interactive soil/veg schemes models follow the gross features of the stable boundary layer quite well • Differences occur in 2m minimum temperature, in long wave incoming radiation and in winds in the morning transition. • To do: analyse runs in relation to turbulence and soil-vegetation schemes. 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

  30. GABLS 3rd case for Single Column ModelIntercomparison and evaluation Modellers are very welcome to join and send in results until the 15th of November 2008. www.knmi.nl/samenw/gabls GABLS3 LES case: Sukanta Basu www.atmo.ttu.edu/basu/gabls3 8th EMS/7th ECAC, Amsterdam, 29 Sep - 3 Oct 2008

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