MPAS-Atmosphere Meshes

Several resolutions of quasi-uniform meshes, plus one refined mesh, are available for download. Each download provides an SCVT mesh on the unit sphere, the mesh connectivity (graph.info) file for the mesh, and partitionings of the mesh (e.g., graph.info.part.32) for various MPI task counts. Other meshes may be available upon request from the MPAS-Atmosphere developers by sending mail to mpas-atmosphere-help AT googlegroups.com.

All mesh files supplied here use double-precision real values. However, running MPAS-Atmosphere in single-precision requires the user to begin with single-precision SCVT mesh files, and all pre-processing steps must be run using a single-precision version of init_atmosphere_model with these mesh files. The double-precision mesh files provided here may be run through the double_to_float_grid converter program to produce a single-precision mesh file.

Quasi-uniform meshes

480-km mesh (2562 horizontal grid cells)

Download the 480-km mesh (1.6 MB)

240-km mesh (10242 horizontal grid cells)

Download the 240-km mesh (6.6 MB)

120-km mesh (40962 horizontal grid cells)

Download the 120-km mesh (26.9 MB)

60-km mesh (163842 horizontal grid cells)

Download the 60-km mesh (111 MB)

30-km mesh (655362 horizontal grid cells)

Download the 30-km mesh (456 MB)

15-km mesh (2621442 horizontal grid cells)

Download the 15-km mesh (1742 MB)

10-km mesh (5898242 horizontal grid cells)

Important note: The 3-d fields that exist in the model at higher resolution can easily exceed the 4 GB limit imposed by the classic netCDF format. When creating atmospheric initial conditions (i.e., the "init.nc" file), and when writing output streams from the model with 3-d fields, it is necessary to use an "io_type" that supports large variables, such as "pnetcdf,cdf5" or "netcdf4". For more information on selecting the "io_type" of a stream, refer to Chapter 5 in the Users' Guide.

Additionally, depending on the amount of memory available, it may be necessary to interpolate the static, geographical fields in parallel. In the v5.0 release, doing this properly requires the use of a special, convex mesh decomposition file -- a regular METIS partition file will not give correct results! In order to process static fields in parallel, one must:

(1) comment-out the code between lines 199 and 204 in src/core_init_atmosphere/mpas_init_atm_cases.F that ordinarily prevents the parallel processing of static fields; and

(2) ensure that the "cvt" partition file prefix (e.g., x1.5898242.cvt.part.) is specified in the config_block_decomp_file_prefix variable in namelist.init_atmosphere.

Download the 10-km mesh (4380 MB)

Variable-resolution meshes

All variable-resolution meshes are supplied with a single refinement region that is centered on 0.0° latitude, 0.0° longitude. This region of refinement may be relocated to other locations on the sphere using the grid_rotate utility, whose usage is described in the MPAS-Atmosphere Users' Guide. The grid_rotate utility may be downloaded here.

92-km – 25-km mesh

This mesh contains 163842 horizontal grid cells, with the refinement region spanning approximately 60 degrees of latitude/longitude.


Download the mesh (135 MB)

46-km – 12-km mesh

This mesh is like the 92-km – 25-km mesh, but with twice the horizontal resolution and 655362 horizontal grid cells.


Download the mesh (592 MB)

60-km – 15-km mesh

This mesh contains 535554 horizontal grid cells, with the refinement region spanning approximately 55 degrees of latitude and 110 degrees of longitude.


Download the mesh (474 MB)

15-km – 3-km mesh

This mesh contains 6488066 horizontal grid cells, with the circular refinement region spanning approximately 60 degrees of latitude/longitude. When using this mesh, there are several crucial changes that must be made to pre-processing steps and to the model configuration:

(1) The 3-d fields that exist in the model at higher resolution can easily exceed the 4 GB limit imposed by the classic netCDF format. When creating atmospheric initial conditions (i.e., the "init.nc" file), and when writing output streams from the model with 3-d fields, it is necessary to use an "io_type" that supports large variables, such as "pnetcdf,cdf5" or "netcdf4". For more information on selecting the "io_type" of a stream, refer to Chapter 5 in the Users' Guide.

(2) Depending on the amount of memory available, it may be necessary to interpolate the static, geographical fields in parallel. In the v5.0 release, doing this properly requires the use of a special, convex mesh decomposition file -- a regular METIS partition file will not give correct results! In order to process static fields in parallel, one must:

(a) comment-out the code between lines 199 and 204 in src/core_init_atmosphere/mpas_init_atm_cases.F that ordinarily prevents the parallel processing of static fields; and

(b) ensure that the "cvt" partition file prefix (e.g., x5.6488066.cvt.part.) is specified in the config_block_decomp_file_prefix variable in namelist.init_atmosphere.

* Note also that when 'config_native_gwd_static = true', each MPI task will read roughly 4 GB of global terrain data, so care must be taken to use enough compute nodes to avoid running out of memory.

(3) When running the model itself with the 15-km – 3-km mesh, it is necessary to set config_apvm_upwinding = 0.0 in the nhyd_model namelist record.




Download the mesh (4560 MB)