Page History

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• All accumulations should start from the beginning of the forecaststep 0
• The initial state (forecast step zero) step 0 must be a part of all forecasts, all members, etc ... .
• The values of accumulated fields must be set to zero for t=0

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• The Control Forecast must be number 0,
• The number of members is identical to the number of all EPS members plus the Control Forecast.

GRIB encoding

TIGGE GRIB2 checking tool

The so called tigge_check tool is a part of ecCodes package. It should be used to validate all GRIB2 files prepared for TIGGE. The tool is checking all encoding details so that only fully compliant TIGGE files following exactly required definitions would pass. Find more information about the tool in the page Data encoding checking tools

Encoding

General GRIB2 key

• gribMasterTablesVersionNumber ie.g <=4
  • =17 (current latest one released in 2019)
    
• localTablesVersion=0
  
  • no local tables should be used

TIGGE Production status of processed data

Octect 36 Octet 20 of section 1 of a GRIB2 message contains the Production status of processed data. The WMO has added two values to table 1.3 Production status of data:

• 4:TIGGE operational products
• 5: TIGGE test products

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Ensemble and deterministic forecasts

Control and perturbed forecasts are identified in section 1 and 4. The following tables explains how to code them in GRIB2:

(*) high-resolution forecast interpolated to ensemble resolution (new request from 2020 for TIGGE, phase III)

• statistically processed (typeOfStatisticalProcessing is set up)

Sample data

• tigge.dems.2t.grib2

Data exchange

The input fields should be split by the output data type, level type and eps number as per below. All steps  should be merged into the same file.

Naming convention

tigge_CCCC_YYYYMMDDHH_VVVV_TT_LL_NNN.grib2   ... for ensemble  forecasts

tigge_CCCC_YYYYMMDDHH_VVVV_TT_LL.grib2   ... for high resolution forecasts

• CCC: centre acronym  (e.g. kwbc for NCEP data)
• YYYYMMDDHH: date * time stamp (e.g. 2019100100 for 0Z run on 2019-10-01)
• VVVV: test/prod
• TT: cf/pf/fc (output type i.e. control forecast/eps member/high resolution forecast)
• LL: pl/sl/pt/pv (level type i.e. pressure/surface/pv level/pt)
• NNN: eps number (cf=000, eps1=001,....)

TIGGE extension (Section 2)

It is proposed that the section 2 for TIGGE fields be the same for all partners. A GRIB2 decoder must decode the section 2 as a TIGGE extension based on the octect 36 of section 1 (Production status of processed data) being 4 or 5.

The format of the TIGGE extension is not yet defined. The section 2 should either be missing or empty.

Checking tool

Use tigge_check  -w -z  (part of ecCodes) to verify GRIB2 encoding of your TIGGE data.

Sample data

• tigge.dems.2t.grib2