GOSI11: High resolution and AGRIF

[oceanaguiar]

• Set up and test ORCA36 demonstrator. Aim for a one year run initially. IA
• ORCA36 and AGRIF to run on ECMWF-HPC, IA currently testing ORCA025.
• Ongoing work with AGRIF at NOC (continuation of IMMERSE work)? AB
• Set up and test AGRIF nests in North Atlantic: 1/12̊ nest in ORCA025, then 1/36̊ nest in ORCA12. Look at impact on overflows and boundary currents (Gulfstream separation and path). DB
• Liaise with P2HR, k-scale and AFESP project. CG, DB, IA

[isabellaascione]

The development of a workflow to run ORCA36 stems from the porting of GOSI9 at NEMO 4.0.4 for ORCA025 to NEMO4.2.1, then 4.2.2, which then becomes the GOSI10 prototype. The steps :

• [x] Porting of GOSI10 workflow for ORCA025 from cylc7 to cylc8: GMED ticket (visible to internal Met Office users only): https://code.metoffice.gov.uk/trac/gmed/ticket/666

• [x] Adapt the GOSI10 workflow for ORCA025 to include options to run on both XC40 (Met Office) and on ECMWF ATOS supercomputer (the workflow includes already the changes from the previous step) https://code.metoffice.gov.uk/trac/roses-u/ticket/579

• [x] Add optional archiving to the ecfs system when running on ECMWF https://code.metoffice.gov.uk/trac/roses-u/ticket/584

• [x] Atmospheric forcings for eORCA36 : https://code.metoffice.gov.uk/trac/roses-u/ticket/593

• [x] Prepare the ancil files (done, but needs to be documented)

• [x] Adapt the workflow to use ORCA36 (ATOS only) https://code.metoffice.gov.uk/trac/roses-u/ticket/592

[isabellaascione]

The ORCA36 model was set up to run a 1 year experiment . The model completed the 1 year experiment on ECMWF ATOS (1 node=240GB) using the following main settings:

• NEMO 4.2
• XIOS2 rev 2610
• time step 120 sec
• atmospheric forcing: CORE interpolated on ORCA36 grid
• bathymetry based on GEBCO 2019 and BedMachine 2 for Antarctica , taken from ftp://ftp.mercator-ocean.fr/download/users/cbricaud/BENCH-eORCA36-INPUT.tar.gz
• initial conditions: WOA13 from ORCA36 demonstrator website ftp://ftp.mercator-ocean.fr/download/users/cbricaud/BENCH-eORCA36-INPUT.tar.gz

Example output ( Surface velocity field averaged from a 24 hourly output on 15-08-1980)

after 1 year run ( Surface velocity field averaged from a 24 hourly output on 31-Dec-1980)

Main differences from the DEMO:

	ORCA36 (This implementation)	ORCA36 DEMO
NEMO nodes	78	100
XIOS nodes	150	200
time to run 1 day	60 min	30 min
ln_isf (*)	false	true
ln_isfcav (*)	false	true
atm forcing	CORE2	IFS
ln_ncar	true	false
ln_ecmwf	false	true
initial conditions	WOA13	WOA13

(*) The input data to build the domain with ln_isfcav have not been provided this file is also not provided