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The value 9 should be used when testing and 8 for operational data.
2)
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Deterministic and
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ensemble data assimilation forecasts
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:
Both systems - deterministic and ensemble DA (analysis or forecast products)
Section 1 | ||||
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Octets | Example perturbed | Analysis products | Forecast productsExample control | |
21 | typeOfProcessedData | 0 | 1 |
Deterministic system (both analysis and forecast products)
Section 4 | |||
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Octets | 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)) |
Ensembe DA system (both analysis and forecast products)
Section 4 | |||
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Octets | 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)) =3 |
Ensemble (section 4, template 4.61) | ||||
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Octets | Example perturbed | Example control | for 2nd eps member of ensemble with 4 members (0/1/2/3) | |
35 | type of ensemble forecast= 255 (missing) | =255 (missing) | ||
36 | perturbation number | = 7 | = 02 | |
37 | number of forecasts in ensemble | = 514 | = 51 |
3) Time component
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of GRIB2 definition
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Examples of GRIB2 files
real-time | re-forecast | ||||
Daily average | Control Perturbed | Control Perturbed | |||
Accumulations | Control Perturbed | Control Perturbed | |||
Instantaneous | Control Perturbed | Control Perturbed | |||
Maximum over the last 6 hours | Control Perturbed | Control Perturbed | |||
deterministic | ensemble DA | ||||
Accumulations | |||||
Instantaneous | |||||
Maximum since previous post-processing | |||||
Minimum since previous post-processing | |||||
Parameter on soil level | |||||
Parameter on soil layer | Minimum over the last 6 hours | Control Perturbed | Control Perturbed