This page contains a few rules on the UERRA parameters. A complete list of all the parameters and GRIB2 encoding is given here.
ECMWF makes available a GRIB decoding library (GRIB-API) for the benefit of the WMO community. GRIB-API can be freely downloaded from here and the documentation can be found here. The GRIB-API provides a simplified access to GRIB2 headers through a set of virtual keys documented her
The version of GRIB-API which can recognise all UERRA parameters is currently under development and should be released to some extent by the 1st half of June. Until then please use the version 1.15.0 which can identify UERRA products as per below (paragraph 1). |
The WMO has added two values to table 1.3 Production status of data:
Section 1 | |||
---|---|---|---|
Octets | Key name | UERRA operational products | UERRA test products |
20 | productionStatusOfProcessedData | 8 | 9 |
Two types of datasets are expected for UERRA - outputs from deterministic and ensemble data assimiliation systems. How they should be encoded in GRIB2 is shown below.
Control and perturbed forecasts are identified in section 1 and 4. The following tables explains how to code them in GRIB2:
Section 1 | |||
---|---|---|---|
Octets | Key name | Analysis products | Forecast products |
21 | typeOfProcessedData | 0 | 1 |
Section 4 | |||
---|---|---|---|
Octets | Key name | Analysis and Forecast products (instantaneous) | Analysis and Forecast products (statisticially processed = accumulated/min/max values ) |
8-9 | productDefinitionTemplateNumber | 0 (Analysis or forecast at a horizontal level or in a horizontal layer at a point in time (grib2/tables/17/4.0.table)) | 8 (Average, accumulation, extreme values or other statistically processed values at a horizontal level or in a horizontal layer in a continuous or non-continuous time interval (grib2/tables/17/4.0.table)) |
Section 4 | |||
---|---|---|---|
Octets | Key name | Analysis and Forecast products (instantaneous) | Analysis and Forecast products (statisticially processed = accumulated/min/max values ) |
8-9 | productDefinitionTemplateNumber | 1 (Individual ensemble forecast, control and perturbed, at a horizontal level or in a horizontal layer at a point in time (grib2/tables/17/4.0.table)) | 11 (Individual ensemble forecast, control and perturbed, at a horizontal level or in a horizontal layer, in a continuous or non-continuous time interval (grib2/tables/17/4.0.table)) |
Ensemble (section 4, template 4.61) | ||
---|---|---|
Octets | Example for 2nd eps member of ensemble with 4 members (0/1/2/3) | |
35 | type of ensemble forecast | 255 (missing) |
36 | perturbation number | 2 |
37 | number of forecasts in ensemble | 4 |
deterministic | ensemble DA | |||
AN | FC | AN | FC | |
Accumulations | FC | FC | ||
Instantaneous | ||||
Maximum since previous post-processing | ||||
Minimum since previous post-processing | ||||
Parameter on soil level | ||||
Parameter on soil layer |