What is GRIB?
GRIB is the WMO's format for binary gridded data. The Metview GRIB interface is based on ecCodes and can handle both GRIB edition 1 and edition 2 seamlessly.
How to use Metview with GRIB?
GRIB files are represented by this icon in the user interface:
The contents of a GRIB file can be inspected with the GRIB Examiner, which can be either started up from user interface (right-click examine on the icon) or from the command line using the following command:
Visualisation on maps
GRIB (with the exception of spherical harmonics fields) can be directly visualised in Metview on a map view. In the user interface just right-click visualise on the icon to get a plot with the default settings. GRIB map plots can be further customised with the Contouring or Wind Plotting icons for scalar fields or vector fields, respectively.
Visualisation on other views
On top of the map-based visualisation we can generate
- vertical cross sections (see Cross Section Data and Cross Section View)
- zonal and meridional averages (see Average Data and Average View)
- Hovmoeller diagrams (see Hovmoeller Data and Hovmoeller View).
It is also possible to extract vertical profiles (see Vertical Profile View) and time series from GRIB data.
The Thermo Data icon can extract thermodynamic profiles which can then be visualised in a tephigram, a skew-t or in an emagarm using Thermo View.
Filtering and interpolation
The GRIB Filter icon provides the means to select a subset of fields from a GRIB file. It (and the MARS Retrieval icon) also contains some parameters, such as Grid, which allow for interpolation to a new grid.
Retrieval from MARS
If you (and your Metview instal
Script language support
Metview provides full support for GRIB from its Macro and Python interfaces. The full list of available functions can be found on the Fieldset Functions page. For examples on how to use ODB from script please see the tutorials and study the Gallery.
Tutorials
The main tutorial about using ODB in Metview can be found here. There is also a shorter tutorial available on this page.
Gallery
The Gallery features a few ODB-related examples showcasing both the ODB Filter and ODB Visualiser icons.
lation) have access to a MARS archive, Metview can retrieve GRIB data via the Mars Retrieval icon. Once the data has been retrieved, the icon text will turn green to indicate that it has been cached; operations such as Visualise and Examine will work on the cached data. If any of the parameters in the Mars Retrieval icon are changed, or if Metview is restarted then the cached data will be removed.