This page contains a few rules on the UERRA parameters. A complete list of all the parameters and GRIB2 encoding is given here.
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UERRA
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parameter rules
Units
- All fields shall use units as defined in GRIB Edition 2. The exact definition for each parameter is linked in Parameter page
Output frequency, levels for an/fc
- all details are available in Parameter page
Accumulations
- All accumulations shall start from the beginning of the forecast
- The initial state (forecast step zero) must not be included (as it should be 0 value field by definition)
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- Instantaneous fields shall be archived with a frequency defined here for each group of parameters and forecast type.
Parameters archived since previous post-processing
- Some parameters (2m tmin/tmax, 10m wind gust) shall be archived with varying length of time range intervals (:
0-1/1-2/2-3/4-5/5-6/6-9/9-12/../27-30 as per here)
Find further in this page GRIB2 files examples including header outputs etc
Fluxes
- The flux sign convention will be is positive downwards.
- Positive evaporation represents condensation.
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Grid and resolution
- Each partner will provide their eps data on their native grid.
- Grids are defined in GRIB2 using an accuracy of 1/1000000 (one millionth) of a degree.
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Ensemble type of
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outputs
- Ensemble member numbering must start from 1
Model levels
- Model level numbering must start from 1
- The Control Forecast must be number 0,
- The number of members is identical to the number of all EPS members plus the Control Forecast.
GRIB2 encoding
ECMWF encoding/decoding Software
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