Running a perpetual year

Hi,

I am hoping to run a perpetual year experiment at 2010 conditions on UKESM AMIP and was hoping you could point me towards some documentation as to the simplest way to achieve this? I have found this page Using the UMUI - UKCA but not one which applies to Rose.

Thank you,
Hannah

Hi Hannah,

Those instructions are somewhat out of date now!

We do have year 2000 timeslice suites available here:

https://www.ukca.ac.uk/wiki/index.php/GA7.1_StratTrop_suites

but these are not UKESM-AMIP configurations and are for 2000 not 2010. There are instructions on how to convert these timeslice runs to transient ones, and you could follow these in reverse, although the tricky bits would be making up the data files.

https://www.ukca.ac.uk/wiki/index.php/GA7.1_StratTrop_suites/convert_to_transient

It’s actually easier to run a 2014 timeslice I think as on Monsoon2 here:

/projects/ancils/cmip6/ancils/n96e/timeslice_2014
/projects/ancils/cmip6/ancils/any/timeslice_2014

you can see directories containing things like the emissions and land fraction files etc., CFC surface concentrations, and volcanic AOD. These would need to be replaced within Rose for the current time-varying ones, as well as editing the radiation panels to make these only have 2014 concentrations for the trace gases. If you want year 2010 instead these numbers will need to be extracted from the historical files and made-up into new files.

For the SSTs/sea-ice you may need to think about how you make these up, i.e. do you take a mean of e.g. 2009-2019 to give a mean 2014, or just take 2014 and repeat that year-on-year. I would suggest taking a mean value to remove particular ENSO features that may exist in a single year (unless these features are perhaps what you want to include!). You could also take data from the UKESM ensembles and make up a climatology from the NEMO output if you wanted to use modelled data.

Tools such as Xancil or ANTS

http://cms.ncas.ac.uk/documents/xancil/

(personally I’ve found Xancil relatively straight-forward to use)

can be used to make up new ancillary files. For UKCA emissions files you can see the Tutorial and the script provided there:

https://www.ukca.ac.uk/wiki/index.php/UKCA_Chemistry_and_Aerosol_vn11.8_Tutorial_5

You should find that if there are any problems in not providing input data the model will exit with an error as it would run out of data as the model passes 2014 (from 2015 onwards for timeseries simulations you would follow a scenario instead).

If you take a look at the AerChemMIP pages

https://code.metoffice.gov.uk/trac/ukcmip6/wiki/AerChemMIPStandardJobs

you can see that there are both pre-Industrial and historial AMIP suites. Doing a diff (e.g. xxdiff -r suite1/ suite2/) will highlight what has been changed between these and essentially those are the files that you need to replace.

Best wishes,
Luke

Hi Luke,

Thank you- this is all very helpful! I definitely need to have 2010 conditions for the anthropogenic emissions but I have the option of using 2010 meteorology or running with changing meteorology so will begin with creating 2010 emissions files.
I was also wondering if the input4mip original files which were used for the greenhouses gases in this wiki: https://code.metoffice.gov.uk/trac/UKESM/wiki/CmipGhg were available. I’m looking specifically for the latitudinal varying methane file which is mentioned as the path to the Jasmin workspace does not seem to exist!

Thanks,
Hannah

The input4mip files are probably available online, but I’m not sure where they would be on JASMIN. I’m not sure who processed these files either but you could contact the Met Office and ask the UKESM team who might know more about this.

Best wishes,
Luke