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Semi-Lagrangian computations in the cycle 46t1r1 of ARPEGE/IFS.

Tuesday 12 February 2019 by Karim Yessad
  Table of contents  

 Abstract:

The general purpose of this documentation is to describe the set of equations used, and also the way to integrate the dynamics of the model with the semi-Lagrangian method currently implemented in ARPEGE/IFS. The following points will be described: semi-Lagrangian formulation and discretisation for different sets of equations, semi-Lagrangian trajectory research, horizontal and vertical interpolations done in the semi-Lagrangian scheme, specific geometric problems met in this type of discretisation. An organigramme is provided. An introduction to tangent linear and adjoint code is provided.


 RESUME:

LE BUT GENERAL DE CETTE DOCUMENTATION EST DE DECRIRE LE JEU D’EQUATIONS UTILISE, ET EGALEMENT LA FACON DE DISCRETISER CES EQUATIONS AVEC UN SCHEMA D’ADVECTION SEMI-LAGRANGIEN TEL QU’IL EST UTILISE DANS ARPEGE/IFS. ON DECRIT LES POINTS SUIVANTS: FORMULATION LAGRANGIENNE DES EQUATIONS, LEUR DISCRETISATION AVEC UN SCHEMA SEMI-LAGRANGIEN, RECHERCHE DE TRAJECTOIRE, INTERPOLATIONS HORIZONTALES ET VERTICALES FAITES DANS LE SCHEMA SEMI-LAGRANGIEN, PROBLEMES DE GEOMETRIE SPECIFIQUES. ON FOURNIT UN ORGANIGRAMME. UNE INTRODUCTION AU CODE TANGENT LINEAIRE ET ADJOINT EST EGALEMENT PROPOSEE.


 Contents:

  • 01/ Introduction.
  • 02/ Definition of Eulerian and semi-Lagrangian schemes.
  • 03/ The 2D equations.
  • 04/ The 3D equations in spherical geometry (ARPEGE/IFS).
  • 05/ Discretisation of the equations: general aspects.
  • 06/ Computation of medium and origin points.
  • 07/ The SL discretisation of the 2D shallow-water system of equations (spherical geometry).
  • 08/ The SL discretisation of the 3D primitive equation model.
  • 09/ The SL discretisation of the fully elastic non hydrostatic (NHEE) model.
  • 10/ The SL discretisation of the quasi elastic non hydrostatic (NHQE) model.
  • 11/ "R" operator.
  • 12/ Computation of longitudes and latitudes on the computational sphere.
  • 13/ Computation of "etadot" at full levels.
  • 14/ Interpolations and weights computations.
  • 15/ Lateral boundary conditions.
  • 16/ 2D shallow water and 3D models organigrammes.
  • 17/ Tangent linear and adjoint codes.
  • 18/ Some distributed memory features.
  • 19/ Specific SL variables in pointer modules, modules and namelists.
  • 20/ Bibliography.
  • Appendix 1/ Description of treatment of NHX for semi-Lagrangian advection.
  • Appendix 2/ Description of dataflow for option LGWADV=T.

titre documents joints

Version cycle 46t1r1

12 February 2019
info document : PDF
611 kb

Version cycle 46t1

7 January 2019
info document : PDF
607.2 kb

Version cycle 46

10 April 2018
info document : PDF
593.1 kb

Version cycle 45

29 June 2017
info document : PDF
632.6 kb

Version cycle 44

7 March 2017
info document : PDF
632.5 kb

Version cycle 43

25 February 2016
info document : PDF
642.5 kb

Version cycle 42

7 July 2015
info document : PDF
642.1 kb

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