Regrid products

The following list outlines the specifications partners must adhere to when submitting data. This ensures consistency and accuracy across all submissions. The agreed-upon format is based on the EASE version 2.0 format recommended by the NSIDC NSIDC EASE Grid version 2.0, utilizing the Lambert Azimuthal Equal Area polar projection. The specific details are as follows:

  • Projection: Based on the EASE version 2.0 format recommended by NSIDC (Lambert Azimuthal Equal Area polar projection).

  • Grid Structure: Square grid with dimensions made up of an even number of pixels, ensuring the poles are located at the intersection of 4 pixels.

  • Orientation: Longitude 0° is vertical, positioned at the bottom for the Northern Hemisphere (NH) below the pole and at the top for the Southern Hemisphere (SH) above the pole.

  • Coverage: The data fully covers areas down to 50° of latitude for both hemispheres (31° at the corners of the grid).

  • Resolution Options:

    • 12.5 km resolution corresponding to 712 x 712 pixels.

    • 25 km resolution corresponding to 356 x 356 pixels.

  • Grid Storage: The grid is stored from the top left corner (0,0), with the i-index varying horizontally to the right and the j-index vertically downwards.

  • Pixel Coordinates: (xc, yc) are the coordinates of the center of each pixel in meters, with the origin at the pole. xc varies horizontally to the right and yc vertically toward the top. For example, the coordinates of the pixel just at the bottom right of the pole are (+res/2, -res/2).

By adhering to these specifications, all consortium partners will ensure uniformity and comparability in the data submitted. Therefore, most datasets have to be regridded before they can be used by the project teams.

How to regrid your products

1. Download & install CDO

The first step is to ensure the CDO tool is available on your system. If not, it can be compiled from source or downloaded from third-party package managers such as conda and mamba.

2. Grid descriptions

2.1 Download the CDO grids descriptions

SIN’XS EASE2-Grid version 2.0 CDO grid descriptions can be downloaded below.

2.2 Download the NetCDF files

SIN’XS EASE2-Grid version 2.0 xc/yc coordinates can be downloaded below.

3. Regrid

Finally, CDO can be used to perform the regridding operation. The following command shows how to regrid a dataset using nearest neighbor interpolation algorithms:

$ cdo remapnn,SINXS_EASE2_N25_356.cdo input.nc output.nc