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This import is available Delft-FEWS versions 2024.02 (basebuild 202402-50714143 or higher) and later.
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- The first time importing a certain forecast (with a specific T0), you may occasionally miss a timestep and get this warning: "WARN - Bad GRIB2 record in file cdms3://ecmwf-forecasts.s3.eu-central-1.amazonaws.com/ecmwf-forecasts?20250807/00z/ifs/0p25/oper/20250807000000-129h-oper-fc.grib2, skipping pos=85720605 cause=Please reduce your request rate. (Service: S3, Status Code: 503, Request ID: GT6E0AJF2J2GT1CZ, Extended Request ID: 0dj/YW262Zwm6s8wg8n4mKOwp1yzZqxNS38x9GnoGQ3o2hlBKu02xOzgHs/IdVT3wl3n5comEM1d/z2FF14+MFrmr7tntDg+9aY85Jns1KA=)". This is a problem and we're working on this (see FEWS-32610).
- Import runtimes can vary a lot (
- The first time importing a certain forecast (with a specific T0), you'll see several warnings like "WARN - Table ecmf/name line scaledValueOfSecondWavelength = missing() ;" → This is not a problem, you can ignore this warning.
- When importing accumulated parameters, the first timestep (00h) will always give a warning like "WARN - Exception while parsing NetCDF data from url cdms3://ecmwf-forecasts.s3.eu-central-1.amazonaws.com/ecmwf-forecasts?20250807/00z/ifs/0p25/oper/20250807000000-0h-oper-fc.grib2. This url will be skipped. Message was: Allocation size must be greater than zero". → This is not a problem, you can ignore this warning.
- The units defined in the .grib2 files don't always seem to be correct (e.g. radiation flux says W/m2 in the .grib2, but it actually seems to be a 3-hour accumulated J/m2 value).
- We have observed that certain parameters (e.g. Pressure_msl) take much longer than other parameters to import. This still needs to be investigated further.
Make the IdMap
Start by manually downloading an example .grib2 file from the ECMWF data browser and opening it in a NetCDF viewer (e.g. Panoply). Identify the parameters you would like to import. How to map the parameters depends on whether a parameter has a z-level (*_height_above_ground) and whether a parameter is accumulated or not (i.e. variables whose name changes in the grib2 file for each timestep).:
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