Ancillaries files for nudging the UKESM1-AMIP suite

Dear CMS,

I am trying to convert the UKESM1-AMIP Vn11.1 free-running suite to a nudged one. It is a copy of u-be303, further developed for adding organic + inorganic Iodine emissions along with wet and dry deposition fluxes.

I am unable to find/locate the ancillaries files required to nudge the suite (u-cv133) on ARCHER2. Can you please point me to where I can get the ancillaries files (e.g. SO2, CH4_biomass) for the Gregorian Calendar? I hope the current sea ice and sst is Okay for the nudged run, if not please point the seaice_amip_n96e.anc and sst_amip_n96e.anc.

Regards, Alok

And I would also like to do this. Though, my related question, for CMS, is how do I convert a free-running model to be nudged? My model is also a copy of u-be303.

Simon

Hi Alok, Simon,

Reanalysis datasets used for nudging can be found here

/work/y07/shared/umshared/ukca/nudging

i.e.

$UMDIR/ukca/nudging

Note that to use ERA5 you will need to include a branch, originally created at vn11.5, for this in ticket um:#5336. I believe that this is the equivalent vn11.1 branch

fcm:um.x_br/dev/mohitdalvi/vn11.1_nudge_era5

note that there are metadata changes needed for Rose.

Instructions for turning a free-running UKESM1 suite to a nudged suite can be found on the UKCA website.

Best wishes,
Luke

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Hi Luke, thanks very much.
Simon

Hi Alok, Simon,

Further, some Gregorian SO2 emissions can be found here:

$UMDIR/ukca/ancil/n96e/cmip6/AeroChemEms/clim_2000/v1/aerocom/

It should be straight-forward to convert 360-day monthly mean emissions files to Gregorian ones using ncatted, e.g. take a copy of the file you want to use, and then run the command

ncatted -O -a calendar_flexible,time,o,l,1 CH4_biomass_low_2014_2020_time_series.nc

which will operate on the copy of the file in place to make use of the calendar_flexible metadata to tell UKCA to use a 360-day file for a Gregorian run. More information on the metadata used in netcdf emissions files can be found on the UKCA website.

Best wishes,
Luke

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