1. 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

2. 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

3. 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

4. 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

5. 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

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

7. 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

8. 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

9. 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

10. 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

11. 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

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

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

14. 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

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

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

17. 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

18. 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

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

20. 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

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

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

23. 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

24. Additional effort is needed
October 2004
26th EWGLAM, Oslo