How to Get New Mesh information for MPAS-A run

[zhangr1011]

Hi,
MPAS-A Team list some specifial meshes for user ingithub, but I want to run a new case with 36km resolution.
Does MPAS-A Team provide code to assist users to obtain new mesh information correctly？
I have generated the mesh and calculate some mesh infomation (lonvertex, latvertex,loncell,latcell and so on).
I have some question about other Mesh information(such as dvEdge, dcEdge,angleEdge)

 

[Ming Chen]

Hi,

Thanks for asking. Mesh generation is a complicated issue and we are working to make the mesh generation more user-friendly. More details can be found in this document: https://www2.mmm.ucar.edu/projects/mpas/tutorial/StAndrews2025/lectures/mesh_generation.pdf

We haven't released the meth generation package yet and don't provide support for mesh generation. Please stay with the available meshes posted in MPAS home page.

Please clarify what questions you have regarding other mesh information. Thanks.

 

[zhangr1011]

Hi,

Thanks for asking. Mesh generation is a complicated issue and we are working to make the mesh generation more user-friendly. More details can be found in this document: https://www2.mmm.ucar.edu/projects/mpas/tutorial/StAndrews2025/lectures/mesh_generation.pdf

We haven't released the meth generation package yet and don't provide support for mesh generation. Please stay with the available meshes posted in MPAS home page.

Please clarify what questions you have regarding other mesh information. Thanks.

Hi Ming Chen,
Thank you for your reply.
I have a new question about the variable "AngleEdge" in the available mesh on MPAS home page. I think This variable "AngleEdge" can be calculated based on variables ”xEdge, yEdge, zEdge, latEdge, lonEdge, verticesOnEdge, xVertex, yVertex, zVertex, nEdges, nVertices“ from a subroutine "set_angleEdge" in MPAS-Tools/mesh_tools/hex_projection/ph_utils.f90 at d1e5341c9150ec7047622a8a02d7ba97e35dbd82 · MPAS-Dev/MPAS-Tools.
However, I use these variables from MPAS-A mesh(x1.40962.grid.nc) to calculate variable "AngleEdge"(called angleEdge_cal). angleEgde_cal different from angleEdge avail in x1.40962.grid.nc (called angleEdge_orial). The attached figure show the diferent bewteen angleEdge_cal and angleEdge_orial. I am curious about what caused the difference between them. Thanks

 

[Ming Chen]

The hex_projection tool projects a Cartesian mesh of perfect hexagons to the sphere using Lambert Conformal projection. The input mesh is a rectangular Cartesian mesh, which is different to global MPAS mesh (e.g., x1.40962.grid.nc). I don't think you can follow the same approach to create regional mesh based on global MPAS mesh.

 

[zhangr1011]

The hex_projection tool projects a Cartesian mesh of perfect hexagons to the sphere using Lambert Conformal projection. The input mesh is a rectangular Cartesian mesh, which is different to global MPAS mesh (e.g., x1.40962.grid.nc). I don't think you can follow the same approach to create regional mesh based on global MPAS mesh.

Hi Ming Chen,
Thanks for your reply. I am not creating a regional grid based on a global grid. My aim is to use the code in the hex_projection tool to calculate the variables I need such as "angleEdge", "dcEdge", "dvEdge", "weightsOnEdge" and so on. the code in the hex_projection tool have different processing methods for calculation in the sphere and plane. What's more, I find that calculation result of the variables "dcEdge", "dvEdge", "weightsOnEdge" are very closed to the original values in global MPAS mesh(e.g., x1.40962.grid.nc). However, the calculation of "angleEdge" have significant deviations.

 

[Ming Chen]

Hi Ming Chen,
Thanks for your reply. I am not creating a regional grid based on a global grid. My aim is to use the code in the hex_projection tool to calculate the variables I need such as "angleEdge", "dcEdge", "dvEdge", "weightsOnEdge" and so on. the code in the hex_projection tool have different processing methods for calculation in the sphere and plane. What's more, I find that calculation result of the variables "dcEdge", "dvEdge", "weightsOnEdge" are very closed to the original values in global MPAS mesh(e.g., x1.40962.grid.nc). However, the calculation of "angleEdge" have significant deviations.

My understanding is that the input mesh used in the hex_projection tool is a rectangular Cartesian mesh, whereas in your calculation, your input mesh is a global mpas mesh (e.g., x1.40962.grid.nc), --- this is the reason why "angleEdge" you obtained is different to the original one.

 

[zhangr1011]

My understanding is that the input mesh used in the hex_projection tool is a rectangular Cartesian mesh, whereas in your calculation, your input mesh is a global mpas mesh (e.g., x1.40962.grid.nc), --- this is the reason why "angleEdge" you obtained is different to the original one.

Thanks， I understand the reason why！

 

[zhangr1011]

Could you share the code to calcucate "angleEdge" with a global maps mesh? I am very want to learn how to calculate "angleEdge" correctly!