This page contains a few rules on the UERRA parameters. A complete list of all the parameters and GRIB2 encoding is given here.

UERRA parameters rules

Units

Accumulations

Instantaneous fields

Parameters archived since previous post-processing

Fluxes

Missing values

Grid and resolution

Types of forecasts

GRIB2 encoding

ECMWF encoding/decoding Software

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).

GRIB2 encoding details

Section 1
Octets Key nameValueDescription
6-7centre8282 (Sweden)
10tablesVersion17latest WMO table with some new definitions for UERRA 
20productionStatusOfProcessedData

8

operational UERRA products

  9test UERRA products
21typeOfProcessedData0Analysis products
  1Forecast products


Deterministic system (both analysis and forecast products)

Section 4
OctetsKey name

Value

Description

8-9productDefinitionTemplateNumber

0

Analysis and Forecast products (instantaneous)

(Analysis or forecast at a horizontal level or in a horizontal layer at a point in time (grib2/tables/17/4.0.table))

  8

Analysis and Forecast products (statisticially processed = accumulated/min/max values)

(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))

Ensembe DA system (both analysis and forecast products)

Section 4
OctetsKey name

Value

Description

8-9productDefinitionTemplateNumber

1

 

Analysis and Forecast products (instantaneous)

(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

Analysis and Forecast products (statisticially processed = accumulated/min/max values)

(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))

35type of ensemble forecast255 missing
36perturbation number2Example for 2nd eps member of ensemble with 4 members (0/1/2/3)
37number of forecasts in ensemble4 

Examples of GRIB2 files

 deterministicensemble DA
 ANFCANFC

Accumulations

(evaporation)

N/A

grib

dump

N/A

grib

dump

Instantaneous    
Maximum since previous post-processing    
Minimum since previous post-processing  

Parameter on soil level

(soil temperature on soil level 1)

grib

dump

grib

dump