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Hirlam Physics Developments

Sander Tijm Hirlam Project leader for physics. Hirlam Physics Developments. Overview. Results of this year Verification Shallow convection Turbulence and convection for mesoscale Tuning of synoptic scale model. Mesoscale Verification Surface Turbulence & shallow convection

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Hirlam Physics Developments

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  1. Sander Tijm Hirlam Project leader for physics Hirlam Physics Developments

  2. Overview • Results of this year • Verification • Shallow convection • Turbulence and convection for mesoscale • Tuning of synoptic scale model

  3. Mesoscale Verification Surface Turbulence & shallow convection Deep convection? Radiation Synoptic scale EPS & boundaries Verification Surface (tuning) Turbulence Shallow convection Deep convection Radiation Wave drag Hirlam physics developments

  4. Results this year • Hirlam physics in IFS (Convection, turbulence and radiation, Sass, Rontu and Niemela) • Moist CBR (Sass & Tijm) • MSO/SSO (Rontu) • Surface scheme (snow and forest, talk of Stefan after this one) • Sloping surfaces radiation (Senkova) • Stable PBL (GABLS, De Bruijn, Perov & friends) • Snow on ice (Vihma) • Lake model (Kourzeneva & Tisler) • Urban characteristics (Baklanov & Mahura)

  5. Moist CBR • Impact on cloud water profiles

  6. Moist CBR • Impact on precipitation

  7. Snow scheme

  8. Verification • Verification working group to check physics of mesoscale model • Cooperation with Aladin • Focus on relatively normal weather, which is challenge for physics • List of cases and progress of work can be found on: http://www.knmi.nl/~tijm/Verif/Verifworkg.html • Verification of models against observations • Model intercomparison • Baseline for future model improvement

  9. Verification

  10. Cloud top temperatures (Zingerle) KF-RK REF Obs

  11. Entrainment/Detrainment • Overprediction of high clouds • Too much deep convection, too little convection of intermediate depth • Too little entrainment (lowering of updraft temperature) and/or detrainment (stopping updraft mass flux) • Can also be seen in shallow cumulus

  12. Specific humidity profiles for ARM with LES (left) and Hirlam 1D using =z-1 and =0.00275 Shallow convection (De Rooy)

  13. Shallow convection • Mass flux profiles for LES (left) and =z-1 + =0.00275 (right)

  14. Shallow convection • Massflux profiles for LES (left) and =z-1 + new  (right) where  depends on cloud depth and critical fraction

  15. Shallow convection qt profiles for ARM with LES (left) and Hirlam SCM (right) with =1/z and new  formulation

  16. zinv EDMF scheme (Siebesma) • Nonlocal (Skewed) transport through strong updrafts in clear and cloudy boundary layer by advective Mass Flux (MF) approach • Remaining (Gaussian) transport done by an Eddy Diffusivity (ED) approach MF ED

  17. Use LES to derive updraft model in clear boundary layer. 0 h (km) 1 0 5 x(km) Updraft at height z composed of those grid points that contain the highest p% of the vertical velocities: p=1%,3%,5%:

  18. EDMF scheme • One scheme for boundary layer and cumulus convection • Will be developed within AROME framework, as an option • Cooperation with ECMWF • After successful implementation in mesoscale model, incorporate in synoptic scale model to limit boundary effects

  19. Surface developments • New surface scheme (Gollvik) for synoptic scale • Extension of surface scheme with lake model (Kourzeneva) • Extension with improved description of snow on ice (Vihma) • Urban impact to be included (Mahura and Baklanov) • Tuning of surface characteristics (Garcia)

  20. Modeled temperature, sensitivity to lake depth(Flake model, Kourzeneva)

  21. Tuning of syn. Hirlam • Sytematic errors in synoptic scale Hirlam: • too much fog • too many and intense small scale lows • too strong convection dynamics feedback (noisy pressure pattern) • Overestimation of evaporation over sea may be an important factor in the development of these phenomena, together with: • Vertical diffusion in stable and neutral conditions • Deep convection parameterization

  22. Tuning of syn. Hirlam

  23. Small scale developments

  24. Summary • Many developments for turbulence, shallow and deep convection, surface modelling. • Shift of main effort towards the mesoscale physics • Synoptic scale remains important, for mesoscale boundaries and SREF • Synoptic physics as close as possible to mesoscale physics, to reduce boundary effects

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