We have found that some ERA5 data from the Climate Data Store (CDS) has become corrupted.

The corrupted data are in the following ERA5 CDS catalogue entries (datasets):

• ERA5 hourly data on single levels from 1979 to present

• ERA5 hourly data on pressure levels from 1979 to present

A page listing the details of the affected fields has been produced -

361 corrupted fields (out of a total of 3.1 billion ERA5 fields) have been identified and replaced.

This corruption issue was resolved on 2021-04-14.

Users that have downloaded any of these affected fields prior to 2021-04-15, are recommended to re-download them.

For reference, this issue has been recorded as a "Resolved issue" in the ERA5: data documentation.

Please note, this issue does NOT affect:

• ERA5 data downloaded from the MARS archive (such as CDS API requests using 'reanalysis-era5-complete')
• ERA5 Monthly CDS catalogue entries (datasets);  these were derived from the ERA5 data on MARS

There is no need to re-download these data.

We apologise for any inconvenience this may have caused you.

Regards, 

ECMWF Support