Last updated: January 2013
The Product Definition Section characterizes the special variable (or product) under consideration. While in GRIB1, a product was determined by the Parameter Number, the Table Number and the Level Type, more meta data are necessary to determine a special product in GRIB2. The main classification is done by the Discipline, the Parameter Category and the Parameter Number. Depending on the product, the Product Definition Section can have different entries. Therefore, products with the same shape of the Product Definition Section are grouped together and have a special template, how meta data in this section looks like. For the products (variables) in the COSMO-Model, only few different templates are necessary.
The following table lists the GRIB2 meta data and associated grib_api keys for the main part of the Product Definition Section of GRIB2 messages, which is common to all products. The sub pages, which can be accessed with the links below, list the full Product Definition Section for the different templates used.
Octets | Key Name | Comments | ||||||||||||||||||
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1-4 | section4Length | Length of section in octets (nn) | ||||||||||||||||||
5 | numberOfSection | Number of section (4) | ||||||||||||||||||
6-7 | NV | Number of coordinate values after Template. Coordinates values are intended to document the vertical discretisation associated with model data on hybrid coordinate vertical levels. A number of zero in octets 6-7 indicates that no such values are present. Otherwise the number corresponds to the whole set of values. | ||||||||||||||||||
8-9 | productDefinitionTemplateNumber | Product definition template number according to Code Table 4.0
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10-xx | Product Definition Template Nr. X to be included here, where X is the Product Definition
Template Number given in octets 8-9.
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[xx+1]-nn | pv | Optional list of coordinate values. These are encoded in IEEE 32-bit floating point format |