Changes between Version 12 and Version 13 of Users/Setup New Configuration/AGRIF-nesting-tool

2017-03-31T21:42:43+02:00 (3 years ago)


  • Users/Setup New Configuration/AGRIF-nesting-tool

    v12 v13  
    44Last edition: '''[[Wikinfo(changed_ts)]]''' by '''[[Wikinfo(changed_by)]]''' 
    6 [[PageOutline(2, ,inline)]] 
    88AGRIF is a package for the integration of adaptive mesh refinement (AMR) features within a multidimensional model written in Fortran and discretized on a structured grid. This nesting capability that allows resolution to be focused over a region of interest by introducing an additional grid has been added to NEMO. In the current implementation only horizontal refinement is available. 
    2020attached movie ITF (mpg): [[AttachmentNum(4)]] 
    22 == Preparing the child model 
     22== 1. Preparing the child model 
    2424One of the features of the AGRIF package is its ability to deal with the use of fixed fine grids in the domain. Here are presented the various basic knowledges every user should have in order to define his child grid domain. 
    26 === Refinement ratio 
     26=== 1.1 Refinement ratio 
    2828In order to implement an embedded model user have to specify his space and time refinement ratio. Every integer number is allowed by AGRIF indeed even and odd refinement ratio in space as well as in time could be chosen. But user have to keep in mind that a too large value could imply numerical troubles, in this way a value between 2 and 5 seems to be an acceptable choice. Localization of fine grid points for odd and even refinement ratio are described in the figure below Concerning time refinement ratio, there is no specific criterion to determine its value but of course the selected value must prevent the model from blowing up. 
    30 === Child Grid Position 
     30=== 1.2 Child Grid Position 
    3232The nested grids are rectangular and are aligned with the parent (coarser) grid within they are nested. $i_{min}$, $i_{max}$, $j_{min}$ and $j_{max}$ refer to the positions of the child grid corners, in terms of its parent grid starting with the value 1 in each space direction. When the user chooses these positions, one has to take care that fine grid is contained in the parent grid. ($i_{min}$,$j_{min}$) are the lower left corner position and ($i_{max}$,$j_{max}$) are the upper right corner position. The indice of the first grid point inside the fine domain is given by the formulae: 
    65 === One-way vs Ywo-way nesting 
     65=== 1.3 One-way vs Ywo-way nesting 
    6767Nested grid simulations can be produced using either 1-way nesting or 2-way nesting. Those options refer to how a coarse grid and the fine grid interact. In both the 1-way and 2-way simulation modes, the fine grid boundary conditions are interpolated from the coarse grid. In a 1-way nest, this is the only information exchange between the grids (coarse-to-fine). In the 2-way nest integration, the fine grid solution are used to update the coarse grid solution for coarse grid points that lie inside the fine grid (coarse-to-fine and fine-to-coarse). User can choose between those both kind of interactions by editing `Agrif_OPA_Update.F90` file located in `NESTING_SRC` directory (as shown below). This file contains a cpp key called `TWO_WAY` if one puts `#define TWO_WAY`, that means 2-way interactive grid nesting is selected at the opposite `#undef TWO_WAY` means 1-way nesting will be applied. 
    71 === Getting the lateral boundary conditions, winds and surface fluxes 
     71== 2. Getting the lateral boundary conditions, winds and surface fluxes 
    7373This step makes use of NEMO/AGRIF Nesting tools package downloadable at the top of this page. Those tools are fully described in its attached documentation. 
    7979The first stage consists in editing the Makefile corresponding to your architecture in `src` directory in order to properly mention the path to your netcdf library with F90 enabled. 
    81 {{{ 
    127127At this step, user should have filled in `` and build coordinates, bathymetry and forcing files for every grid mentioned in this file. 
    129 == Running the model 
     129== 3. Running the model 
    131 === Input data 
     131== Input data 
    132132data needed to run with OPA are of two types : the namelists and the forcing files (already created thanks to nesting tools). Concerning namelists one need to provide one namelist by grid, the naming convention is the same than the one for forcing files. 
    170170And we need only a weight file called `` in the running directory, while core forcing files corresponds to the coarse grid input files. 
    172 === Output data 
     172== Output data 
    173173output files are NetCDF or DIMG (key_dimgout activated) files giving the diagnostics at points T,U,V,W of the Arakawa C grid. For fine grids output files, the naming convention is exactly the same than the one mentioned above namely a different prefix for each grid of the hierarchy. The output files contain the both ghostcells, mentioned before, at the boundaries, so depending the visualization tool used, user can have the value zero at the boundaries of child grids. Note that the text file called ocean.ouput containing all the information printed during the run is also created for fine grids. 
    175 === Development Team 
     175== Development Team 
    177177||Organization      ||Name            ||Developments                                                                                    ||contact                 || 
    180180||LMC/IMAG,Grenoble ||Florian Lemarié ||Nesting tools,New AGRIF interpolation schemes (PPM/ENO),Numerical issues                        || || 
    182 === Support 
     182== Support 
    185 === Known Users 
     185== Known Users 
    186186||Organization           ||Name                                          ||Region of interest         ||Configuration          || 
    187187||LEGI Grenoble FRANCE   ||Jean-Marc Molines                             ||Gulf of Mexico             ||NATL3/NATL4            || 
    193193||Mercator OCean         || Jerome Chanut                                ||North Atlantic             ||CREG025, CREG12        || 
    195 === References 
     195== References 
    196196 * [ AGRIF ] web page - (Laurent Debreu, LMC-IMAG) 
    197197 * Nesting Tool: