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Any data in the CDS catalogue can be accessed in these two ways. And since such data is kept online, access is usually fast. Some parts of the ERA5 dataset are not listed in the CDS catalogue. These are only accessible through the CDS API service. An example is ERA5 model level data that resides in the ECMWF's MARS tape archive. The extraction of such data from tape can lead to significantly longer retrieval times than data that is available online.
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When requesting ERA5 data from the CDS in NetCDF (web or CDS API), users should not request ERA5 reanalysis atmospheric data, wave data, and ensemble data in one request. This is because the data has different spatial grids, which can cause issues for the current grib to NetCDF converter and produce incorrect results. |
Option B: Download ERA5 family
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data stored on MARS tape archive (no data selection can be made from the CDS download form) - SLOW ACCESS
Although some flavours of the ERA5 family data is not online in the CDS (i.e. not available through the interactive web download form), it is accessible through CDS API. This embraces ERA5-complete, ERA5.1-complete and ERA5-complete-preliminary, which provide data in the 'raw' format as they were produced:
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