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Spectral transforms in the cycle 46t1r1 of ARPEGE/IFS.

Karim Yessad — 2019-02-12T00:00:00Z

Abstract:
ARPEGE/IFS, ALADIN and AROME are spectral models, so this documentation has for purpose to describe the spectral transforms done. The present note has for aim to give a brief summary of the spectral method (how to compute Legendre polynomials, spectral transforms) and to describe parts of the code performing spectral transforms (organigramme). RESUME:
ARPEGE/IFS, ALADIN ET AROME SONT DES MODELES SPECTRAUX, EN CONSEQUENCE CETTE DOCUMENTATION A POUR BUT DE DECRIRE LES (…)

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Horizontal diffusion computations in cycle 46t1r1 of ARPEGE/IFS.

Karim Yessad — 2019-02-12T00:00:00Z

Abstract:
This documentation recalls some basics about horizontal diffusion schemes, and describes how they are implemented in ARPEGE/IFS and its LAM (limited area model) counterpart. The ECMWF way of implementing them (which is slightly different from the METEO-FRANCE one) is not described in detail. There is a main horizontal diffusion scheme, a sponge and a Rayleigh friction. An organigramme is provided. RESUME:
CETTE DOCUMENTATION RAPPELLE QUELQUES NOTIONS SUR LES SCHEMAS DE (…)

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Integration of the model equations, and eulerian dynamics, in the cycle 46t1r1 of ARPEGE/IFS.

Karim Yessad — 2019-02-12T00:00:00Z

Abstract:
This documentation can be seen as a long introduction to modeling. 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. Two points will be examined in detail in this documentation: the Eulerian dynamics and the discretisations used. For some other aspects (semi-Lagrangian dynamics, physics, spectral transforms, horizontal diffusion, semi-implicit scheme), this documentation will not provide (…)

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

Karim Yessad — 2019-02-12T00:00:00Z

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 (…)

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Semi-Implicit spectral computations and predictor-corrector schemes in the cycle 46t1r1 of ARPEGE/IFS.

Karim Yessad — 2019-02-12T00:00:00Z

Abstract:
This documentation describes two types of schemes allowing to stabilize the numerical discretizations of the models: the semi-implicit scheme and the iterative centred-implicit scheme (sometimes called predictor-corrector scheme). An algorithmic description to different types of equations, and some technical information (organigramme) are provided. RESUME:
CETTE DOCUMENTATION DECRIT DEUX TYPES DE SCHEMAS PERMETTANT DE STABILISER LES DISCRETISATIONS NUMERIQUES DES MODELES: LE (…)

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Digital filtering initialisation in the cycle 46t1r1 of ARPEGE/IFS.

Karim Yessad — 2019-02-12T00:00:00Z

Abstract:
This documentation describes the digital filtering initialisation (DFI) and its implementation in ARPEGE/IFS. Some theoretical aspects are recalled. The way of implementing the DFI in ARPEGE/IFS is then described, and an organigramme is provided. A namelist is provided. RESUME:
CETTE DOCUMENTATION DECRIT L'INITIALISATION PAR FILTRES DIGITAUX (DFI) ET LE CODE ASSOCIE DANS ARPEGE/IFS. ON RAPPELLE QUELQUES NOTIONS THEORIQUES. ON DECRIT LA FACON DONT LES DFI ONT ETE CODES DANS (…)

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Modification of ARPEGE necessary to include the EGA-SA, "case (ii)"

Pierre BÃ©nard — 2014-05-27T17:54:06Z

This memo is a specific application of "Continuity equation for non-spherical geometries..." for the case of a spherical planet with meridionally varying gravity but shallow-atmosphere approximation.
This specific case may be implemented with very minimal changes to the existing code, while allowing to assess the magnitude of gravity errors of the spherical approximation.

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Continuity equation for non-spherical geometries in mass-coordinates

This memo describes the transformation of physically-consistent atmospheric systems in non-spherical geometries from geopotential-based to mass-based coordinates. Only the continuity equation is examined here.

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Non-Hydrostatic Model versioned documentations (2013)

2013-01-31T00:00:00Z

In this page you will find the official scientific documentation of the Aladin NH model (authors : Pierre BÃ©nard and Jan Masek). The old versions of the documentation are archived (version 1 1995-2003, version 2.0.0 of December 2003, version 2.1 of December 2004, version 3.0 of July 2011), and for the latest version (version 3.1 of January 2013), the contents of the document is detailed : General remarks Euler equation Shallow-atmosphere and "classical" approximations Mass-based coordinate (…)

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"A and B" : Design of the hybrid vertical coordinate (eta), 2008

2009-12-16T14:14:00Z

These documents describe a new method for the setting the vertical levels in the "A and B" namelists. These describe a more intuitive method to define the hybrid pressure terrain-following coordinate in ARPEGE/ALADIN/AROME/...
A separate file contains the external FORTRAN program and Linux shell. Documentation about the "A and B" program version 2 with pressure-top equals zero (December 2008) version 1 with pressure-top equals zero (December 2004) version 1 with pressure-top non equal to (…)

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