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ERA5 data from 1950-1978 for int2lm
Dear all,
we would like to use ERA5 data to create forcings for the CCLM model. On the DKRZ server we found files for the years 1979 to 2021 that can be processed via the int2lm tool.
However, we would like to extend the time span to the years 1950-1978. Since the data for these years seems to be not present on the DKRZ server, we started to download the ERA5 data for 1950-1978 from the Copernicus web site (https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-pressure-levels-preliminary-back-extension). Unfortunately, the downloaded files cannot be directly used with the int2lm tool. The files differ in variables and vertical levels with respect to the DKRZ ones. Is there a tool or some defined protocol to convert the Copernicus data to the needed format? If not, where does the DKRZ data stem from?
With best regrads,
Sven Karsten
The data on the Copernicus web site are horizontally and vertically interpolated data. The int2lm ready cas… files at DKRZ are based on the original, ie. not interpolated, ERA5 output that is stored under /pool/data/ERA5. The DKRZ has not yet transferred the original data from 1950-1978.
Dear Burkhardt,
thank you for your fast reply. We would have some further questions:
“Option B: Download ERA5 family data that is NOT listed in the CDS online catalogue – SLOW ACCESS ”?
With best regards,
Sven Karsetn
> Is this original data for 1950-1978 accessable from the Copernicus web site via the steps described at https://confluence.ecmwf.int/display/CKB/How+to+download+ERA5 under
> “Option B: Download ERA5 family data that is NOT listed in the CDS online catalogue – SLOW ACCESS”?
I do not know.
> If not, where to get this original data?
I also do not know, you may ask at DKRZ how they do it.
> Is it alternatively possible to use the interpolated data, available via the Copernicus web site, for the int2lm tool?
Yes, it would be, but you have to write a converter program on your own.
Hello Sven,
as you know, there is no data at the DKRZ for periods before 1979:
https://modvis.dkrz.de/bm0146/ERA5/statusE5.html
The data from the Copernicus web site do not cover the period before 1979. And it is very likely that only the MARS archive is giving you access to all model levels you need.
It is always a good idea to contact the DKRZ . You should ask the people at beratung@dkrz.de about their plans to handle the data before 1979.
What I know is that there is at the moment no access at all to data before 1979 . This is what I got from ECMWF :
“Here we document the ERA5 dataset, which, eventually, will cover the period from January 1950 onwards. Complete ERA5 data released so far covers the period from 1979 and continues to be extended forward in near real time.”
Bye, Ronny
Dear Sven,
from what I know, the non-interpolated data is only available from the ECMWF MARS archive. If you do not have access, I don’t know.
If somehow you will succeed to retrieve the data before 1979, you then can use the program “era5tocaf” from the RedC:
https://redc.clm-community.eu/projects/int2lm/wiki/Pre-Processor_Programs
to convert it to int2lm readable files. This is the one that has been used to produce the cas-files stored in /pool/data/ERA5 at DKRZ .
Best wishes,
Susanne
Dear Susanne, Ronny and Burkhardt,
thanks a lot for your support. We will contact the DKRZ support and have a look at the proposed converter tool.
Have a nice day,
Sven Karsten
There are already prepared directories for the time 1950-1978 under /pool/data/ERA5. However, they are still empty.
@Sven : please put a short note in the forum when you get the response from DKRZ