Version 14 (modified by cbricaud, 3 years ago) (diff)

Analysis Tools

This is the current list for all available NEMO analysis tools.This section is open for submissions, if you feel something is missing, add your own tool.

NOTE: the NEMO system team is not responsible for the support of all packages. In each package description you will find the email of the author or the person in charge of that package's support.


SAXO is a package (~400 routines, ~60 000 code lines) used to easily and quickly visualize and analyze models outputs or data observations. It is based on IDL and contains a Graphic User Interface. Developed in collaboration with LOCEAN researchers, it allows to explore four dimension data which may be gridded or irregularly spaced. It is particularly adapted to the "Arakawa C grid" discretization used in NEMO. In addition to graphical procedures, interpolation modules and other things …, it contains a set of programs dedicated to oceanographic diagnostics.

Support, Author: saxo-dev@…



ARIANE is a FORTRAN code dedicated to the computation of 3D streamlines in a given velocity field (as the output of an Ocean General Circulation Model) and subsequent water masses analyses. ARIANE is used extensively as a diagnostic tool to analyze simulations run with the LODYC OPA OGCM. However, any 3D non-divergent transport field, gridded on any C-grid, could virtually be used as an input. Ariane has been adapated to analyze ROMS outputs. ARIANE is by essence an off-line diagnostic tool. It cannot be used for on-line trajectories computations in an OGCM. ARIANE (or its former versions) is being used by different groups at LPO and by people from other institutions in France (such as LODYC, LEGOS and LSCE) and abroad (in Italy, at ENEA). ARIANE was used by our group in the framework of TRACMASS, a EEC funded MAST III research project (see the GLADIATORs' home page for further information) for the period 06/1998-05/2001. ARIANE also received support from INSU in the framework of an «Action Thématique Innovante» project, for the period 09/1998-08/2000.

The earliest developments date back to Summer 1992, with the first coding of the analytical scheme that computes 3D streamlines in a C-gridded velocity field [see Speich, 1992 for some pioneer visualizations]. This scheme is still in use in ARIANE, and defines the core of all our other downstream diagnostics related to the tracing of water masses in an OGCM.

Such off-line diagnostics were initiated by Döös [1995] and we drew our inspiration from his approach to develop our own methodology. Most of the technical details associated with our computations are described in the appendices of three recent papers [Blanke and Raynaud, 1997; Blanke et al., 1999; 2001], together with some useful figures.

None of the present work could have been done without the availability of a high-performance OGCM. We wish to thank here the whole OPA modeling group, led by Pascale Delecluse and Gurvan Madec at LODYC, for its constant effort to develop, improve and validate this OGCM.

Though still crude, ARIANE is able to perform a large number of interesting computations. Here follow some of the possible options associated with the use of ARIANE:

  • QUALITATIVE diagnostics: a few particles (typically less than 10), with a steady recording of the positions along their trajectories.
  • QUANTITATIVE diagnostics: many (thousands of !) particles, with statistics available for the initial and final positions, and with the diagnostic of the main pathways.
  • FORWARD or BACKWARD integrations (useful to trace back the origins of a given water mass).
  • can be run on a PERIODIC (global) grid, or on a BASIN (smaller sub-domain).
  • the diagnostics can be related to any of the OGCM tracer fields.
  • widely tested on a Cray C94 architecture, but very stable on 32bits machines too (double precision is required for best results).


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