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In MIR, parameters have been classified into groups, or "classes", which have an associated default interpolation method. As a result some parameters will now have a significantly different default interpolation method compared to EMOSLIB. Most parameters will use the default linear method in MIR, while some specific classes will use a different method:
| Method | Classes affected |
|---|---|
| nearest neigbour |
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| nearest with |
| Land-Sea Mask |
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| Linear (default) |
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| Info | ||
|---|---|---|
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| MIR does not use any special processing for precipitation fields like EMOSLIB. |
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MIR brings a number of improvements in the sub-area and cropping operations.
Consistency with fields from dissemination
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MIR will now move the boundaries inwards onto an underlying global grid with a point at latitude=0, longitude=0. This behaviour is a change in respect to EMOSLIB, and it brings it closer to the product generation for dissemination.
Subareas on reduced Gaussian grids
EMOSLIB only supports sub-area operations on regular Gaussian or lat-lon grids. MIR is capable of cropping sub-areas and frames directly on reduced Gaussian grids, including the octahedral reduced Gaussian grid.
Support for shifted grids
MIR can work with shifted grids, with no point at latitude=0, longitude=0. An example would be:
| No Format |
|---|
AREA=89.5/0.5/-89.5/359.5, GRID=1.0/1.0 |
This is done automatically provided both the N-S and E-W boundary limits are divisible by the corresponding increments without remainder. This represents a change in respect to EMOSLIB, which would adjust the area to fit. In the previous example, it would go to the more conventional area 90/0/-90/359.
Usage of IFS spectral transform library
While EMOSLIB has its own implementation for the transformations from spherical harmonics to grid space, MIR makes use of the spectral transform library, called Trans from the IFS model. That means MIR behaviour is more consistent to what is done in the model, and will immediately benefit from any improvements made in Trans.
Fractions for longitudes
Rotated Grids