1. Preliminary validation results of the prognostic 3d-TKE-scheme
Gerd Vogel, Ursula Schubert
DWD Potsdam
Zurich, September 2005
FE 14

2. Outlook
Operational LM-prediction
May 30, 2004
Lindenberg

3. Outlook May 30, 2004 Op. scheme (3tls) Mellor&Yamada (3tls)
3d pTKE-scheme
Mellor&Yamada (2tls, ALM)
May 30, 2004
Meteorol.and Atm. Physics, 2005, 88, 23-38
Gassmann, A.:

4. Data of vertical sounding systems available from MO Lindenberg (DWD)
Operational radiosonde ascents (temperature, humidity, wind components, every 6 hours, up to 25 km)
LIDAR-measurements (water vapour, all 10 min between 500m m, provided by MPI Hamburg only during field experiments)
Microwave profiler data (temperature , all 10 min, up to 25 km)
Windprofiler-, RASS-, SODAR-systems (wind components , virtual temperature, all 10 min, 200m-3000m)
Data of vertical sounding systems available from MO Lindenberg (DWD)

5. Outlook
Average over 8 days (weak winds only) in May and June 2004 (Lindenberg)

6. Outlook
Average over 8 days (weak winds only) during May and June 2004 (Lindenberg)

7. Prognostic 3d-TKE scheme
Microwave data
Prognostic 3d-TKE scheme
Comparisons with operational cross-sections based on LME-predictions daily available:

8. Basic features of the prognostic 3d-TKE scheme
(momentum)
specified flux
components:
(heat)
simplified anisotropic
diffusion approach
Prandtl-Kolmogorov-
specification
of vertical diffusion
aspect ratio
[Dunst (1980)]

9. Outlook
Vertical velocity (12 UTC) 400 m
LMK 1d pTKE
LMK 3d pTKE

10. Vertical velocity (12 UTC)
Outlook
Vertical velocity (12 UTC)
LMK 1d pTKE
LMK 3d pTKE

11. Zonal height-cross section (j=175) Vertical velocity 12 UTC
LMK 1d pTKE
LMK 3d pTKE

14. Conclusions
A proper accuracy check of the turbulence parameterisations used in the LM will only be possible if the model forcing from the surface has been improved. It’s intended to replace soil moisture, precipitation and radiation balance values at surface by measure- ments (or simulated data basing on them like soil moisture) in the whole LMK area.
Versatile vertical soundings available from Lindenberg (DWD) enable us to study thoroughly the changing boundary layer structures during the day. Based on them the model behaviour can be evaluated more comprehensively due to continuous compa- risons between measured and simulated meteorological quantities along the vertical.
The implementation of the horizontal heat and momentum fluxes improves the phy-sical content of the scheme. In order to find out how accurately the present prognostic 3d-TKE scheme describes the reality (e.g. simulation of convection rolls), further validation studies are necessary, also including satellite data which often reveal such convection rolls in nature, too.