PP file format

A brief description of the PP format with links to software utilities and code tables.

Introduction

PP-format is a record-based binary format used in a number of the BADC's datasets. It is a Met Office proprietary format so is mainly associated with Met Office products.

The BADC holds a number of software utilities available for handling PP. These including decoding, unpacking, subsetting, converting and byte-swapping. Please see the XCONV/CONVSH pages for details on the software available.

Description of PP-format

A description of the binary PP-format header is available. This describes how the binary pp data files should be interpreted to provide information on grid size, variable, processing etc.

Parameter codes in PP

The variables in the pp files are defined by their "STASH" ("Spatial and Temporal Averaging and Storage Handling") codes. These are a numerical code which are used to identify a given variable from a lookup table. There are separate lookup tables for variables from atmospheric, ocean, slab ocean and ocean wave models. The UKMO NWP data is generated by runs of the atmosphere model, while climate model runs (such as HadCM3) can output both atmospheric and ocean variables.

The STASHMASTER files are available here: atmosphere ocean.

The variables are also grouped together in a broader classification by their numerical field code, and this a much broader grouping. For example, "temperature at 1.5m" and "temperature on pressure levels" would have different stash codes (), but the same field code-"16". The field codes file holds a list of numerical field codes and their full variable names.

A file listing the relationship between stash and field codes is available here. An example of the mapping is:

STASH code	Field code	Description of diagnoistic
00001	8	PSTAR AFTER TIMESTEP
00002	56	U COMPNT OF WIND AFTER TIMESTEP
00003	57	V COMPNT OF WIND AFTER TIMESTEP
00004	19	THETA AFTER TIMESTEP

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