Gregorian seaice and sst from 1979 to 2014


I am preparing to run some long nudged simulations (1979 to around 2014) on ARCHER2. I have converted several emission ancillaries to gregorian format using advice here:

But, seaice and sst files have a different format and I’m unsure how to check what they contain. I want seaice and sst to match the simulation period. How can I check what period the gregorian .anc files in this folder cover?




Doesn’t xconv do ?


I was going to suggest xconv too. I believe that the Reynolds dataset begins in September 1981, so for some nudged runs we’re planning we might use the HadISST dataset we made up for CCMI2022. However, this only is valid through to the end of 2018 so we will have to mix-and-match with Reynolds as we want to go up to 2022.

Best wishes,

Hi Grenville, Luke,

I wasn’t aware xconv worked on .anc files. Thanks.

All available files do indeed start in 1981. We’d really prefer to start our simulations in 1979 to catch the peak in European and North American anthropogenic emissions.

Luke, is the HadISST dataset you mention suitable? It would be great to use this if possible. Our runs will end at 2014 so the 2018 cutoff is no problem.

All the best,



The files here:
may be an alternative. They are timeseries .anc files.

I know how to adapt .nc files so they can be used in nudged simultations. But, I have no clue as to how to adapt .anc files. Could you point me in the right direction please?



Hi Leighton,

So long as the file contains monthly means it should work for nudging - problems would occur with daily values.

The SSTs used for CCMI2022 are on Monsoon2, located here:


and run from 1870 to the end of 2019, although due to the way the files are processed I believe that the advice is not to use the last 2 years (2018 & 2019).

These may actually be equivalent files up until the last few years - for CCMI2022 we needed to run until 2018.

Best wishes,

Thanks for the info and advice Luke!

This topic was automatically closed 2 days after the last reply. New replies are no longer allowed.