Physics developments in ALADIN: towards higher resolution Neva Pristov Environmental Agency of Slovenia Meteorological office Overview of work done by others in various countries October 2004 26th EWGLAM, Oslo

Content Cloudiness Orographic forcing Radiation Microphysics and convection T. Haiden, A. Kann, H. Seidl, R. Brožkova, ... B. Carty, F. Bouyssel, R. Brožkova, J-F Geleyn, M. Derkova, R. Mladek, J. Cedilnik, D. Drvar J-F Geleyn, G. Hello, N. Pristov, Y. Bouteloup, M. Derkova Luc Gerard October 2004 26th EWGLAM, Oslo

Cloudiness Problem Method Underestimating of low cloudiness Structure of lifted inversions poorly predicted Overestimated diurnal cycle of temperature Method Experiments (1-d and 3-d) with different cloudiness parameterizations Study effects of vertical diffusion parameterization on inversion October 2004 26th EWGLAM, Oslo

Low cloudiness sensitivity experiment horizontal diffusion of temperature - on Seidl/Kann scheme Improved stratus forecast, but areal coverage still insufficient horizontal diffusion of temperature - off October 2004 26th EWGLAM, Oslo

Cloudiness Scheme modifications modify the vertical profile of critical relative humidity - to get medium and high clouds starting to appear at lower relative humidity values. tuning of the X-R function in Xu-Randall cloudiness scheme use of the random/maximum overlap for clouds instead of the random overlap October 2004 26th EWGLAM, Oslo

Cloudiness Total cloudiness previous new Amount of clouds is more realistically distributed October 2004 26th EWGLAM, Oslo

Orographic forcing modification in orography drag parametrization revised dependencies of the drag on the Froude number a lift orthogonal to the geostrophic wind and not any more to the real wind replacing envelope orography by a mean orography October 2004 26th EWGLAM, Oslo

Orographic forcing Experiments (Semi-Academical) on ALPIA domain 10km 5km 2.5km 1.25km Experiments (Semi-Academical) on ALPIA domain Using new drag/lift scheme The new scheme is tuned to be resolution independent Parameterization is needed for horizontal mesh sizes from ~ 5 km The envelope can be suppressed by the new lift scheme The thin line between param / no param is not clear October 2004 26th EWGLAM, Oslo

Orographic forcing envelope disappearance and drag/lift improvement + more realistic flow around the mountain ranges + better wind scores at 850 hPa and around + less upwind exaggerated precipitations on mountain flanks (unfortunately) without any shift in position, + increased compatibility with the theory of sub-grid mountainous forcing, - too weak 10 m winds near mountains - decreased foehn effect that was apparently well tuned before, - slightly negative upper air geopotential scores October 2004 26th EWGLAM, Oslo

Orographic forcing Total precipitation sum 62 days SOP MAP 1999 Envelope orography, old drag scheme Difference Total precipitation sum 62 days SOP MAP 1999 Bias reduced by 25% Maxima around moutains peaks decreased No improvement in distribution Mean orography, new drag scheme Difference Analyses October 2004 26th EWGLAM, Oslo

Radiation completely modifies the thermal computations 2 modes: 'statistical' - 'basic' call at each time-step; 'self-learning' - some chosen time steps are far more expensive to better tune the 'classical' ones used in-between October 2004 26th EWGLAM, Oslo

Radiation CTS+EWS+EBL decomposition of the thermal radiative exchange terms in absence of scattering CTS EWS EBL October 2004 26th EWGLAM, Oslo

Radiation Scores with respect to FMR (new ARPEGE) Geopotential Better on all domains October 2004 26th EWGLAM, Oslo

Radiation Scores with respect to FMR (new ARPEGE) Temperature Better for Europe and N20 (except at very top) Worse for Tropics and S20 October 2004 26th EWGLAM, Oslo

Radiation Computation of optical depths using the gazeous RRTM transmission functions CTS EWS EBL Comparison of fluxes – encouraging results October 2004 26th EWGLAM, Oslo

Combined effects of improvements Storm 14 September 2003 Black Sea MSL pressure Cloudiness, radiation, drag, without envelope + SLHD C- 1007 hPa B- 1000 hPa Cloudiness, radiation, drag, without envelope A- 986 hPa October 2004 26th EWGLAM, Oslo

Microphysics and convection An integrated approach Microphysics 3 prognostic: vapour, cloud ice, cloud liquid water 2 diagnostic: precipitation liquid and solid Fluxes of water and heat Parametrization of WBF and riming process Convective updraught detrains condensates (no precipitation) Downdraught October 2004 26th EWGLAM, Oslo

Microphysics and convection Comparision of 2 experiments Precipitating Water condensing in the updraught is immediately precipitated to the ground Integrated Updraught detrains condensates October 2004 26th EWGLAM, Oslo

Microphysics and convection Squall line 14 August 1999 Western Belgium MSL pressure and precipitation ‘precipitating’ integrated October 2004 26th EWGLAM, Oslo

Microphysics and convection Squall line 14 August 1999 Western Belgium ‘precipitating’ integrated Precipitation continues to increase Produce less precipitation Maximum of precipitation on right place Smoother pressure field October 2004 26th EWGLAM, Oslo

Microphysics and convection Vertical cross section – cloud condensates and T ‘precipitating’ integrated More cloud ice October 2004 26th EWGLAM, Oslo

Microphysics and convection Vertical cross section – updraught vertical velocity ‘precipitating’ integrated Extended updraught activity Higher velocities October 2004 26th EWGLAM, Oslo

Microphysics and convection Problem Not enough precipitation because of vertical distribution of condensates Solution Detrainment connected with Entrainment by the same cloud at lover level Neighbourhood clouds October 2004 26th EWGLAM, Oslo

Additional effort is needed October 2004 26th EWGLAM, Oslo