Dear all, I have a question about ERA5 EDA ensemble members mean and Spread.
When downloading those files in NetCDF experimental format from CDS (Copernicus data storage) I can see that the members are identified by a number ranging from 0 to 9.
If I well understand there is 9 members and an unperturbed control. My question is how can I identify the control ? Is it the number 0 in the ranging?
Also how is calculated the ensemble mean? Is it the mean of the 10 members or the mean of the 9 members excluding the control member?
Thanks for your help.
Thomas
2 Comments
Michela Giusti
Hi,
please have a look at the following link:
ERA5: data documentation#Ensemblemeansandstandarddeviations
Regards
Michela
thomas cordonnier
Hi Michela,
Thanks for your help and the link. But I can't find all the information that I am looking for.
I understand that "Both these quantities are calculated from all the 10-members (i.e., including the control).", so ok, it is the mean and standard deviation ("spread") of the 10 members, including control.
However I still don't know how to identify the control member (number"0"?) when downloading Ensemble members. Also when I do the mean or stdev of the 10 members (manual calculation from the 10 members) at a specific time and lon/lat I don't get exacly the same value as the mean or standard deviation directly downloaded from CDS.
So I am wondering how are calculated those values.
Best regards
Thomas