For more details of changes in the IFS cycle 40r1, please see Cycle 40r1 release notes. Note the following additional changes to the SCM:

  • semi-Lagrangian advection is now available and set as the default (previously only Eulerian advection was possible).
  • the simplified physics is now available as an alternative to the full physics. The simplified physics is used in the tangent-linear code at ECMWF.
  • new diagnostics quantities available (type of PBL, convection type, lowermost and uppermost levels of convection, ...)

Namelists

There are two namelist files in the scm-40r1.ref-oifs/test-run directory:
           namelist.trref_winds_rel  and  namelist.trref_winds_rel.simpl

The former one defines non-linear physics, the latter one the simplified physics (you may be surprised how close the results from the two packages are). We expect most users to use the full non-linear physics option.

Radiation namelist

It is important to set NRADINT=0 in the namelist &NAERAD. If not the model will abort as the default configuration is for 3D runs where the IFS uses a reduced grid to compute the radiation.

Semi-Lagrangian

By default the semi-Lagrangian scheme is activated (LSLAG=.T.) with the physics being averaged along a trajectory (LSLPHY=.T.). This follows the defaults in the IFS.

If you like to use Eulerian advection set LSLAG=.F., reduce the model timestep (don't forget to change number of time steps accordingly) and disable the semi-Lagrangian physics by setting LSLPHY=.F.