There are two options for accessing ESMF regridding functionality: integrated and offline.
**Integrated regridding** means that the weights are generated via subroutine calls during the
execution of the user's code. **Offline regridding** means that the weights are generated
by a separate application from the user code.
Offline weight generation is provided by the
ESMF_RegridWeightGen application
which internally uses the ESMF regridding API.
The tables on this page organize the grids and capabilities supported by ESMF regridding,
as well some numerical results from specific cases.

Supported | Not supported |

Supported, but not automatically tested |

The 2D meshes are composed of quadrilateral and triangular elements, and the 3D meshes are composed of hexahedral elements. Cubed sphere grids are supported as an ESMF Mesh. Two coordinate systems are currently supported in the integrated regridding, Cartesian and spherical.

2D regional grids | 3D regional grids | ||||

Logically rectangular | Mesh | Logically rectangular | Mesh | ||

2D regional grids | Logically rectangular | ||||

Mesh | |||||

3D regional grids | Logically rectangular | ||||

Mesh |

2D global grids | 2D regional grids | ||||

Logically rectangular | Mesh | Logically rectangular | Mesh | ||

2D global grids | Logically rectangular | ||||

Mesh | |||||

2D regional grids | Logically rectangular | ||||

Mesh |

The 2D meshes are composed of quadrilateral and triangular elements. Cubed sphere grids are supported as an ESMF Mesh. The offline regridding is currently restricted to spherical coordinate systems.

2D global grids | 2D regional grids | ||||

Logically rectangular | Mesh | Logically rectangular | Mesh | ||

2D global grids | Logically rectangular | ||||

Mesh | |||||

2D regional grids | Logically rectangular | ||||

Mesh |

There are several different capabilities available in each of these applications. The following symbols and keywords are used:

Capabilities | Description | Bilinear | Patch | Conservative |
---|---|---|---|---|

Regridding | ||||

Masking (Logically rectangular grids only) |
Destination | |||

Source | ||||

Ignore unmapped points | ||||

Pole options | Full circle average | N/A | ||

N-point average | N/A | |||

No pole |

Capabilities | Description | Bilinear | Patch | Conservative |
---|---|---|---|---|

Regridding | ||||

Masking (Logically rectangular grids only) |
Destination | |||

Source | ||||

Ignore unmapped points | ||||

Pole options | Full circle average | N/A | ||

N-point average | N/A | |||

No pole |

The following table presents some specific examples of numerical results of the ESMF regridding capabilities. The numerical test cases that were evaluated for this table were computed using global grids. The results were collected from the ESMF_RegridWeightGenCheck external demo. All of the results in this table were generated by regridding a second order spherical harmonic-like field F = 2 + cos^2(theta)*cos(2*phi).

Methods | Grids [source to destination] |
Largest negative weight | Interpolation average error | Conservation relative error | Notes |
---|---|---|---|---|---|

Bilinear | Lat-lon 1 degree to Lat-lon 2.5 degree |
-5.99e-15 | 1.04e-04 | N/A | This test was done with no masking and the full circle average pole option. |

Cubed sphere grid (ne30np4-t2.nc) to Lat-lon 1.9x2.5 degree (fv1.9x2.5_050503.nc) |
0 | 1.87e-04 | N/A | ||

Patch | Lat-lon 1 degree to Lat-lon 2.5 degree |
-6.21e-02 | 7.61e-05 | N/A | This test was done with no masking and the full circle average pole option. |

Cubed sphere grid (ne30np4-t2.nc) to Lat-lon 1.9x2.5 degree (fv1.9x2.5_050503.nc) |
-6.40e-02 | 1.24e-04 | N/A | ||

Conservative | Lat-lon 1 degree to Lat-lon 2.5 degree |
0 | 5.49e-04 | 8.73e-10 | This test was done with no masking and the no pole option. |

Cubed sphere grid (ne30np4-t2.nc) to Lat-lon 1.9x2.5 degree (fv1.9x2.5_050503.nc) |
0 | 1.17e-03 | 2.48e-13 |

Numerical Recipes in C - The Art of Scientific Computing, Second Edition, pp. 123-128.

New York, Cambridge University Press, 1999.

The superconvergent patch recovery technique and data transfer operators in 3d plasticity problems.

Finite Elements in Analysis and Design, 43(8), 2007.

A modified superconvergent patch recovery method and its application to large deformation problems.

Finite Elements in Analysis and Design, 40(5-6), 2004.