ERA5-ERA5T Differences Sep-Nov 2021: Updated Data and Analysis Available Now!

As we notified earlier, the preliminary ERA5T data from a 3-month period ranging from Sep-Nov 2021 (and probably also part of December) will differ from the final, validated ERA5 data.

Now, final and validated ERA5 data for additional months of Oct-Nov 2021 have been made available in windPRO and EMD-API.

Based on the newly available data, we have updated our analysis on wind-speed differences arising from this issue. Our findings are unchanged from previous analysis/notes:

– differences in monthly average are small (typically below 0.1 m/s)

– differences for individual, hourly timestamps can be as large as 10-15 m/s

If you have used the ERA5T data from Sep-Dec 2021, we recommend that you follow the advice in our original notification. Read more from the links below:

– Updated EMD-Analysis with impact on 100m global wind speeds (updated 2021-12-27)
– Recommendations if you have used ERA5T data for months Sep-Dec 2021 (original notification)
– windPRO wiki-page on ERA5 and ERA5T

Figure showing: November 2021 – Maximum absolute difference in 100m instantaneous wind speed (individual hourly time-series samples) for ERA5 vs ERA5T.