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MIR does not support the 12-point interpolation method, used by EMOSLIB for rotated grids. Therefore, the default interpolation method used is the linear. Rotated spherical harmonics are not supported in MIR or EMOSLIB.

Land-sea mask values

When interpolating the land-sea mask field, MIR returns fractional values greater than or equal to 0 and less than or equal to 1 whereas EMOSLIB returns only 0s and 1s.  Users should regard land-sea mask values greater than or equal to 0.5 as representing land points and those less than 0.5 as representing sea points.

Treatment of values at the poles

MIR is providing different values at the poles to those obtained with EMOSLIB for interpolations to regular latitude-longitude grids which include points at latitudes 90ºN or 90ºS.

Known Issues

RESOL=AV uses wrong intermediate Gaussian grid

When using RESOL=AV and transforming from spectral to grid, the corresponding intermediate Gaussian grid to be used should be the cubic reduced Gaussian grid by default (i.e., O = T+1), as described above. However, at this point MIR uses a full (regular) gaussian grid with linear truncation (i.e., F = (T+1)/2).

Winds on rotated grids

There are known issues with wind fields when working with rotated grids. In particular, wind speeds are correct but the direction is wrong due to a problem in computing the angles.

Performance for small subareas

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