A variety of subgrid-scale physical processes are taken into account by parameterization
schemes. Some parts of the present physics package of the COSMO-Model have been adapted
from the former operational hydrostatic models EM/DM, but some are based on new
developments or have been taken over by GME or the IFS. The following table gives
a short overview on the parameterization schemes used operationally
and on additional options implemented so far.
| Grid-Scale Clouds and Precipitation |
- Cloud water condensation and evaporation by saturation adjustment.
- Precipitation formation by a bulk microphysics parameterization including
water vapour, cloud water, cloud ice, rain and snow with 3D transport for the
precipitating phases.
- Option for a new bulk scheme including graupel.
- Option for a simpler column equilibrium scheme.
|
| Subgrid-Scale Clouds |
- Subgrid-scale cloudiness is interpreted by an empirical function
depending on relative humidity and height. A corresponding cloud water
content is also interpreted. Option for a statistical subgrid-scale cloud
diagnostic for turbulence.
|
| Moist Convection |
- Tiedtke (1989) mass-flux convection scheme with equilibrium closure based
on moisture convergence. Option for a modified closure based on CAPE.
- Reduced Tiedtke scheme for shallow convection only.
|
| Radiation |
- δ-two stream radiation scheme after Ritter and Geylen
(1992) for short- and longwave fluxes (employing eight spectral intervals);
full cloud-radiation feedback.
|
| Subgrid-Scale Orography |
- Subgrid-scale orography (SSO) scheme by Lott and Miller (1997) which
deals explicitly with a low-level flow that is blocked when the
subgrid-scale orography is sufficiently high.
|
| Subgrid-Scale Turbulence |
- Prognostic turbulent kinetic energy closure at level 2.5 including effects
from subgrid-scale condensation and from thermal circulations.
- Option for a diagnostic second order K-closure of hierarchy level 2
for vertical turbulent fluxes.
- Preliminary option for calculation of horizontal turbulent diffusion in
terrain following coordinates (3D Turbulence).
|
| Surface Layer |
- A Surface layer scheme (based on turbulent kinetic energy) including a
laminar-turbulent roughness layer.
- Option for a stability-dependent drag-law formulation of momentum,
heat and moisture fluxes according to similarity theory (Louis, 1979).
|
| Soil Processes |
- Multi-layer version of the former two-layer soil model after Jacobsen and
Heise (1982) based on the direct numerical solution of the heat conduction
equation. Snow and interception storage are included.
- Option for the (old) two-layer soil model employing the extended
force-restore method still included.
|
| Sea Ice Scheme |
- Based on work by Mironov and Ritter (DWD)
|
| FLake Model |
- A Fresh-water Lake model by Mironov (2008)
|