Timetable

Versions

On 9 February 2016, ECMWF will update the default versions of its GRIB API, EMOSLIB, Magics, Metview packages to the versions specified in the table below.

On the same day, the default version of MARS will be changed to use these new default libraries.

Please see the Release notes for full details of the changes implemented in each package.

Important changes

GRIB API

GRIB API version 1.14.5 provides support both for decoding data on the octahedral reduced Gaussian grid and for the new simulated satellite image GRIB products based on the octahedral grid which will be introduced with the Implementation of IFS cycle 41r2 in operations.In particular, the new computed keys gridName and isOctahedral are available to aid identification of the type of reduced Gaussian grid:

• For an octahedral grid, isOctahedral=1; otherwise, isOctahedral=0
• For an octahedral with 1280 latitudes between pole and equator gridName=O1280; for an original reduced Gaussian grid with 640 latitudes between pole and equator, gridName=N640 while the corresponding regular Gaussian grid has gridName=F640.

The update also includes two other important changes:

• The encoding of the keys affecting the description of the area and grid resolution (latitudeOfFirstGridPoint[InDegrees], latitudeOfLastGridPoint[InDegrees] longitudeOfFirstGridPoint[InDegrees] longitudeOfLasstGridPoint[InDegrees], iDirectionIncrement[InDegrees], jDirectionIncrement[InDegrees]) is restricted to millidegrees for GRIB 1 fields.  An attempt to represent these values with sub-millidegree precision via an interpolation with MARS or directly with EMOSLIB will result in an error and the retrieval will fail.  User programs setting these keys are unaffected.
  
• The default type for the mars keys "stream" and "class" in GRIB 1 messages is changed from "integer" to "string".  Users that have created GRIB index files using these keys will need to rebuild the index.

EMOSLIB

Along with support for interpolation of the octahedral reduced Gaussian grid, the update to EMOSLIB introduces two important changes:

• GRIBEX support is discontinued.  Code calling GRIBEX will abort.
• A bug has been fixed which will change results for interpolations from global grid point fields to regular lat-lon or regular Gaussian grids.  The problem and the specific cases where differences can occur are described in  Bug fix implemented in EMOSLIB 4.3.x.

Magics

Magics 2.26.2 has been linked with version 1.14.5 of the GRIB API library to provide support for visualisation of data on the octahedral reduced Gaussian grid.

Metview

Metview 4.6.4 has been linked with EMOSLIB 4.3.7 and GRIB API 1.14.5 to provide support for visualisation of data on the octahedral reduced Gaussian grid.

The option to plot the classic meteograms based on HRES data (the 10 days Metgram type option for the Metgram function) is discontinued with the introduction of the octahedral reduced Gaussian grid.

MARS

The default version of MARS to be introduced on 9 February 2016 is using EMOSLIB 4.3.7 and GRIB API 1.14.6 so is subject to the changes described for these packages.

How to use the new versions for testing before the update of 9 February 2016

The new versions of the software packages can be selected on ecgate by using the commands:

module load metview/new

module load Magics/new

module switch emos/new

module switch grib_api/new

mars -t

and on cca and ccb with:

module switch emos/new

module switch grib_api/new

mars -t

How to revert to the old versions in case of problems after the update of 9 February 2016

Users that experience problems with the new default software packages after the update of 9 February will be able to revert to the old default versions.  These can be selected on ecgate with the commands:

module load metview/old

module load Magics/old

module switch emos/old

module switch grib_api/old

and on cca and ccb with

module switch emos/old

module switch grib_api/old

The previous default version of MARS can be used with 'mars -t -p'.