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PathKeywordsNew keywordsMIR BehaviourEMOSLIB Behaviour
Red

RESOL=AUTO,

GRID=1.0/1.0

TRUNCATION=AUTO,

INTGRID=AUTO,

GRID=1.0/1.0

Default Behaviour.

Transformation from T1279 to an intermediate F90 full (regular) Gaussian grid (with an automatic truncation to T179) followed by a grid-to-grid interpolation from the F90 grid to 1.0/1.0.

Default Behaviour.

Direct transformation from T1279 to 1.0/1.0, with an automatic truncation to T213 according to EMOSLIB's truncation table

Green

RESOL=AV,

GRID=1.0/1.0

TRUNCATION=NONE,

INTGRID=O1280,

GRID=1.0/1.0

Transformation from T1279 to the corresponding intermediate reduced octahedral Gaussian O1280, before going to 1.0/1.0.

Direct transformation from T1279 to 1.0/1.0, with no truncation.
Blue

RESOL=179,

GRID=F90,

and then

GRID=1.0/1.0

TRUNCATION=179,

INTGRID=F90,

GRID=1.0/1.0

Transformation from T1279 to the F90 full (regular) Gaussian grid (with a user-specified truncation to T179) followed by a grid-to-grid interpolation from the F90 grid to 1.0/1.0.Same as in MIR, but a separate MARS request is needed for each of the two steps.



Expand
titleLegacy emoslib EMOSLIB behaviour >

Anchor
emoslib
emoslib
With EMOSLIB spectral fields are by default automatically truncated before interpolation to grid fields to reduce data volumes and spurious aliased values. When automatic truncation is applied MARS issues a warning message like INTFB: Resolution automatically set to ....

The truncation can be controlled using the keywords truncation and intgrid. Users wanting to post-process at the full archived resolution can specify truncation = none in the request. Note that high resolutions might need more resources to carry out post-processing.

Legacy
emoslib
EMOSLIB default spectral truncation wave number for given lat/lon grid increment ∆.
Grid increment [deg]Truncation
2.5 ≤ ∆     T63
1.5 ≤ ∆ < 2.5T106
0.6 ≤ ∆ < 1.5T213
0.4 ≤ ∆ < 0.6T319
0.3 ≤ ∆ < 0.4T511
0.15 ≤ ∆ < 0.3 T799
0.09 ≤ ∆ < 0.15T1279
0.0  ≤ ∆ < 0.09T2047



Note
titleIntermediate Gaussian grids

When doing spectral to grid transformations, MIR may produce smoother fields compared to EMOSLIB. This is due to the fact that MIR uses the intermediate gaussian grid, while EMOSLIB does this transformation directly.

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