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ALADIN documentation / 3DVAR aspects, 2007 updated
Article published on November 2002
last modification on 21 February 2007

This note gives a detailed description of the algorithmic part, for the benefit of phasing, remote installations and development. A theoretical overview is recalled for completeness with the technical section. A "User’s guide" is added for the general users of 3dvar.

  • Formalism of incremental variational analysis
    • 3dvar
    • Background error covariance matrix B
    • Preconditioning
    • 4dvar
  • Data flow and code organisation
    • Screening
    • 3dvar minimisation
    • 4dvar minimisation
  • User’s guide : scripts and namelists
    • Sequences of execution and Input/Output
    • Most important namelist parameters
    • How to check for the execution ?
    • Frequently encountered ... crashes
  • Domain definitions in ALADIN
  • Aspects of the data distribution on MPP machines

The 3dvar ALADIN was also presented during the 1st ALADIN phasing and maintenance workskop, Budapest, November 2002.