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CEMS-Flood data are available in GRIB(2) and NetCDF(4) formats.
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| borderColor | grey |
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| title | GRIB |
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GRIdded Binary (or General Regularly-distributed Information in Binary form) is a common data format used in meteorology and standardised by the World Meteorological Organisation. - There are two versions of GRIB: GRIB edition 1 (GRIB1) and edition 2 (GRIB2).
- CEMS-Flood data is available in GRIB2.
- It is archived in GRIB2 in the Meteorological Archival and Retrieval System (MARS) at ECMWF, see the MARS user documentation for further information.
- Further information on the data format is available in the What are GRIB files page on the Copernicus Knowledge Base.
There are 2 principal ways to work with GRIB2 files: 1. ecCodes A library developed at ECMWF consisting of a set of tools to code and decode GRIBs, as well as other formats. The ecCodes command-line utilities are commonly used by the meteorology community. Please consult the Copernicus Knowledge Base page How to read GRIB files for an overview of the commands available. 2. CFGRIB
A Python interface to the eccodes library. It is one of the supported backends of Xarray. Please consult the Open CEMS-Flood data page for example of using CFGRIB with CEMS-Flood data. | Code Block |
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| language | bash |
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| title | Example of EFAS GRIB2 data structure for river discharge reforecast |
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| collapse | true |
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| <xarray.Dataset>
Dimensions: (step: 2, y: 950, x: 1000)
Coordinates:
number int64 ...
time datetime64[ns] ...
* step (step) timedelta64[ns] 00:00:00 06:00:00
surface int64 ...
valid_time (step) datetime64[ns] ...
Dimensions without coordinates: y, x
Data variables:
dis06 (step, y, x) float32 ... |
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| borderColor | grey |
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| borderStyle | dashed |
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| title | NetCDF |
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The Network Common Data Format (NetCDF), is a machine-independent data format widely used in the scientific community to store array-oriented multi-dimensional data. CEMS-Flood datasets are conformant with the version 4 data model (NetCDF-4) and Version 1.7 of the CF convention. | Code Block |
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| language | bash |
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| title | Example of EFAS NetCDF data structure for historical river discharge |
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| collapse | true |
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| dimensions:
time = 4 ;
y = 950 ;
x = 1000 ;
variables:
int64 time(time) ;
time:long_name = "initial time of forecast" ;
time:standard_name = "forecast_reference_time" ;
time:units = "seconds since 1970-01-01" ;
time:calendar = "proleptic_gregorian" ;
double step ;
step:_FillValue = NaN ;
step:long_name = "time since forecast_reference_time" ;
step:standard_name = "forecast_period" ;
step:units = "hours" ;
double surface ;
surface:_FillValue = NaN ;
surface:long_name = "original GRIB coordinate for key: level(surface)" ;
surface:units = "1" ;
double valid_time(time) ;
valid_time:_FillValue = NaN ;
valid_time:standard_name = "time" ;
valid_time:long_name = "time" ;
valid_time:units = "seconds since 1970-01-01" ;
valid_time:calendar = "proleptic_gregorian" ;
float dis06(time, y, x) ;
dis06:_FillValue = NaNf ;
dis06:GRIB_paramId = 240023LL ;
dis06:GRIB_dataType = "sfo" ;
dis06:GRIB_numberOfPoints = 950000LL ;
dis06:GRIB_typeOfLevel = "surface" ;
dis06:GRIB_stepUnits = 1LL ;
dis06:GRIB_stepType = "avg" ;
dis06:GRIB_gridType = "lambert_azimuthal_equal_area" ;
dis06:GRIB_NV = 0LL ;
dis06:GRIB_cfName = "unknown" ;
dis06:GRIB_cfVarName = "dis06" ;
dis06:GRIB_gridDefinitionDescription = "Lambert azimuthal equal area projection " ;
dis06:GRIB_missingValue = 9999LL ;
dis06:GRIB_name = "Mean discharge in the last 6 hours" ;
dis06:GRIB_shortName = "dis06" ;
dis06:GRIB_units = "m**3 s**-1" ;
dis06:long_name = "Mean discharge in the last 6 hours" ;
dis06:units = "m**3 s**-1" ;
dis06:standard_name = "unknown" ;
dis06:coordinates = "time step surface valid_time" ;
// global attributes:
:GRIB_edition = 2LL ;
:GRIB_centre = "ecmf" ;
:GRIB_centreDescription = "European Centre for Medium-Range Weather Forecasts" ;
:GRIB_subCentre = 0LL ;
:Conventions = "CF-1.7" ;
:institution = "European Centre for Medium-Range Weather Forecasts" ;
:history = "2021-11-23T10:25 GRIB to CDM+CF via cfgrib-0.9.9.0/ecCodes-2.23.0 with {\"source\": \"adaptor.mars.external-1637662774.2155154-5073-2-b5af81a6-2574-467a-81e4-8ad529c6fd1e.grib\", \"filter_by_keys\": {}, \"encode_cf\": [\"parameter\", \"time\", \"geography\", \"vertical\"]}" ;
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GRIB2 is the official supported format, however, NetCDF4 is also supported for some of the datasets (see Table 1). More information on the two formats can be found in the GRIB2 and NetCDF4 sections.
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| Service Provider | Dataset | Format |
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EFAS
| Historical | GRIB2 and NetCDF4 |
| Forecast | GRIB2 and NetCDF4 |
| Reforecast | GRIB2 and NetCDF4 |
| Seasonal | GRIB2 and NetCDF4 |
| Seasonal Reforecast | GRIB2 and NetCDF4 |
| Upstream area | NetCDF4 |
Elevation (Digital Elevation Model) | NetCDF4 |
| Soil depth | NetCDF4 |
| Field capacity | NetCDF4 |
| Wilting point | NetCDF4 |
| GloFAS | Historical | GRIB2 |
| Forecast | GRIB2 and NetCDF4 |
| Reforecast | GRIB2 |
| Seasonal | GRIB2 |
| Seasonal Reforecast | GRIB2 |
| Upstream area | NetCDF4 |
| Elevation (Digitial Elevation Model) | NetCDF4 |
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CEMS-Flood has two services for different spatial domains, EFAS (for Europe) and GloFAS (for the world), each consisting of:
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