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&NAMDIM
  NUNDEFLD=0,

Plotting

data is spectral

The shallow-water model outputs fields only in spectral space. To plot the fields they will first need converting to gridpoint form.

The figure at the top of this page was generated using 'Metview'. The 'GRIB Filter' icon was used:

READ,
    DATA       = 'ICMSHepc9+000594',
    INTERPOLATION = LINEAR FIT,
    GRID       = 5/5,
    GAUSSIAN   = REGULAR

For more information about Metview please contact openifs-support@ecmwf.int 

Code notes

Other switches are used internally:

! LR2D : 2D shallow water or vorticity model

! LRSHW : 2D shallow water model related to the shallow-water model setup are used internally: LR2D & LRSHW.

The IFS starts with a huge amount of setup. The setup are mainly done under the routines called su0yoma and su0yomb (all setup routines starts by su). They are themselves called by the first layer of the model cnt0. Then, the following layers cnt1, cnt2, cnt3 are called (forget about them for now) and finally, we reach cnt4 which contains the time loop. The routine which does one time step is called stepo (there are many different way of calling it as you could see in the "jungle" routine cnt4).

A time step starts in spectral space (all prognostic fields are in spectral space).

A standard time step (corresponding to time t) goes like thisas: the spectral fields (which are at time t) are transformed to GP space (Legendre invinverse transform. followed by Fourier invinverse transform.). Then the grid point computations start. At the end of the GP computation, the prognostic fields for next time step t+dt contain the explicit guess + half of the semi-implicit (SI) correction. This guess is transformed back to spectral space where we solve the SI problem to compute the other half of the SI correction. End of time step ....is reached. At the beginning of next time step, the new spectral fields will then be the new fields for the new time t...

In the current routine suspecb, you can chose choose between idealized cases or read one level of a grib flie file (N2DINI is the key for this choice). suspecb is called at cnt3 level . - the first part of the GP computations are done from a routine called CPG2 which is a very simplified version of the 3D GP computation, the other (lagged, mostly SL computation) are done in CPG2_LAG Both cpg2 and cpg2_lag are called by the driver routine gp_model which is also the driver routine of the 3D GP computation. - the spectral computation are done under spc2 spc.