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Introduction

This presentation: a few explanations, many pointers to web sites and to paths on French super-computers. A large part of this presentation is a bird's eye inventory of input files for LMDZ.

A lot of this, you do not have to know if you use libIGCM, because choosing and getting the necessary files will be automated. Note: there are regular training sessions for libIGCM. The information here may be useful if you have non-standard needs.

LMDZ may be coupled with other models:

The sets of input files and input parameters vary with the set of models you couple. For example, you need to provide sea-surface temperature in an input file only if you do not couple LMDZ with an ocean model.

LMDZ itself has several configurations which impact the input files it requires:

  • Longitude-latitude dynamics or Dynamico
  • 1 or 3 dimensions.
  • Nudging or not.
  • Realistic or idealized "physical" part of the model.

For example, you need to provide special input files for nudging.

In the rest of this presentation, we will look only at the required input for a "base setup":

  • LMDZ alone (no coupling with another model), longitude-latitude dynamics
  • 3 dimensions
  • No nudging
  • Realistic (terrestrial) physics and surface (well, more or less: the continents and relief are there, but no Orchidee)

We may distinguish several types of input, conceptually:

  • Initial state
  • Boundary conditions: surface conditions and solar irradiance
  • Forcing inside the atmosphere: concentration of greenhouse gases, ozone field, fields of aerosols
  • Number and behaviour of tracers
  • Behaviour of the gcm: choosing between alternate physical parameterizations, choosing parameters within physical parameterizations, dynamics parameters, etc.
  • Choice of output

From a practical computer-side point of view, we will have to provide several types of input files:

  • NetCDF files
  • Text files
    • files in a special format for a procedure called getin
    • a file in a special format to describe tracers
    • XML files