Changes between Version 7 and Version 8 of Users/SetupNewConfiguration/AGRIF-nesting-tool

Timestamp:

2017-03-10T11:45:38+01:00 (7 years ago)

Author:

cbricaud

Comment:

--

Users/SetupNewConfiguration/AGRIF-nesting-tool

@@ -51 +51 @@
 Let's consider an example with a root coarse grid (G0) which has two child grids (G1) and (G2), and G1 has one child grid (G3). Space and time refinement factors are equal to 3, in this case the AGRIF_FixedGrids.in file syntax is the following one : 
 
+||imin  ||imax  ||jmin  ||jmax  ||spacerefx     ||spacerefy     ||timeref||             
+||2     ||      ||      ||      ||      ||      ||      ||(G0) has 2 child grids : (G1) and (G2)||      
+||40    ||70    ||2     ||30    ||3     ||3     ||3     ||positions and refinement factors for (G1)||
+||110   ||130   ||50    ||80    ||3     ||3     ||3     ||positions and refinement factors for (G2)||
+||1     ||      ||      ||      ||      ||      ||      ||(G1) has 1 child grid (G3)||
+||20    ||40    ||8     ||30    ||3     ||3     ||3     ||positions and refinement factors for (G3)||
+||0     ||      ||      ||      ||      ||      ||      ||(G2) has no child grid||
+||0     ||      ||      ||      ||      ||      ||      ||(G3) has no child grid ||
+
+[[Image(AGRIF-Hierarchy_medium.jpg​)]]
+
+=1.3 One-way vs Ywo-way nesting=
+
+Nested 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.
+
+[[Image(AGRIF_Organigrame.jpg​​)]]
+
+
+
+==2. Getting the lateral boundary conditions, winds and surface fluxes==
+
+This 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.[[BR]]
+
+Please refer to this file for a detailed approach of this package:[[BR]]
+
+
+Let's just consider the current chapter as a reminder of the functioning of nesting tools.[[BR]]
+
+
+The 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.[[BR]]
+
+
+{{{
+
+#elisha
+
+cd Nesting_tools/src
+vi Makefile_g95
+}}}
+
+The various architecture currently supported are : 
+|| Architecture         ||Compiler||
+||PC/Linux      ||ifort, pgf90, g95||
+||Alpha Compaq ||       f95||
+||IBM   ||xlf90||
+||MacOS         ||g95||
+
+hen once Makefile is properly edited, user can compile the code and check the result in bin/ directory. One should find five executables namely create_coordinates.exe, create_bathy.exe, create_data.exe , create_restart.exe (if needed) and create_restart_trc.exe (when using PISCES for instance).
+
+
+{{{
+#elisha
+
+make -f Makefile_g95
+cd ../bin
+}}}
+
+There is a sample namlist called agulhas to create forcing files for agulhas area. You may edit or copy this file to add your own forcing files, change the zoom area and adjust interpolation parameters.
+
+
+{{{
+#elisha
+
+./create_coordinated.exe agulhas (step 1, always needed)
+
+./create_bathy.exe agulhas (step 2, always needed)
+
+./create_data agulhas (step 3, not needed when using online interpolation)
+}}}
+
+
+This order must be kept because create_bathy.exe requires a coordinates file build by create_coordinates.exe in the same way create_data.exe makes use of a bathymetry file produced by create_bathy.exe.[[BR]]
+
+
+Both grid and bathymetry creation are needed to perform an AGRIF run. For fluxes (step 3), the user is free to use the nesting tools or online interpolation :[[BR]]
+
+- when using the nesting tools, every forcing files needed for a traditional NEMO run (i.e. without AGRIF) have to be created for fine grids except specific files like runoff.[[BR]]
+
+- when using online interpolation ,the child grid will use the coarse grid input files during the run, performing an interpolation on the fly (bilinear or bicubic), so we have to provide an weight file (see [https://forge.ipsl.jussieu.fr/nemo/wiki/Users/SetupNewConfiguration/Weight-creator On the Fly Interpolation])[[BR]]
+
+In case of a multiple nests configuration, one have to fill in AGRIF_FixedGrids.in in accordance with the prefix given by nesting tools code. Let's consider the example used in section 1.2, (G1) forcing files must be named with '1_' prefix, (G2) with '2_' and (G3) with '3_'. But if (G1) and (G2) definition lines are inverted, (G2) should correspond to '1_' prefix and (G1) to '2_'. When running nesting tools program if a whole set of '1_' prefix files is already present in bin/ directory the program will create by default '2_' prefix files. In the case of a number of level of zoom greater than 2, when considering level n one has just to fill in namelist file by replacing forcing files by those created at level n-1.[[BR]]
+
+At this step, user should have filled in AGRIF_FixedGrids.in and build coordinates, bathymetry and forcing files for every grid mentioned in this file. [[BR]]
+
+
+ 
+