XIOS output

Applies to: AWI-CM3 v3.1 and later, and every AWI-ESM3. AWI-CM3 v3.0 has no IO server.

Output is controlled via XIOS, configured by the XML files in the work directory.

The XML in the work directory is generated

Those XML files are rendered from Jinja templates under esm_tools/namelists/, not copied from a fixed set. Editing file_def.xml in a finished work directory changes nothing about the next leg, because the next run renders a fresh copy over the top of it. Change the template, or change the switch that selects which template is used.

The templates live in two places, one per component:

OpenIFS: esm_tools/namelists/oifs/{cycle}/xios/, so 43r3 and 48r1 have their own sets.
FESOM2: esm_tools/namelists/fesom2/xios_xml/, with a second set in xios_xml_cmip7/.

The other half of the trap is naming. The unsuffixed files are OpenIFS and the _fesom suffixed ones are FESOM2, so editing file_def_fesom.xml.j2 when you meant OpenIFS output, or the reverse, is easy and silent.

Switch to the CMIP7 output set

Two switches, one per component, both off by default:

oifs:
    cmip7_cmor_output: true
fesom:
    cmip7_cmor_output: true

For OpenIFS this swaps file_def, field_def, axis_def and grid_def for the set under xios/cmip7/. For FESOM2 it swaps the whole template directory to xios_xml_cmip7, which writes many variables at several frequencies in place of the default minimal monthly set of roughly 28 that mirrors upstream namelist.io.

Do not confuse cmip7_cmor_output with oifs.mip. mip chooses the forcing that goes in, the greenhouse gases, aerosols and ozone, from either the CMIP6 or the CMIP7 pool. cmip7_cmor_output chooses what comes out. They are independent switches and either combination runs.

Regridded output

Applies to: FESOM2 with cmip7_cmor_output. The default file_def ignores both switches.

The CMIP7 FESOM2 templates can write regular latitude longitude output alongside the native unstructured output, at the same frequency as its native counterpart:

fesom:
    regrid_surface_output: true    # 2D fields
    regrid_3d_output: true         # temp, salt, unod, vnod, w, bolus_*, N2, Kv, Av, ...

Both default to true, because the cost was measured rather than guessed: the 2D set came out under one percent of wall time and under 1 GB per simulated year at half a degree, and adding the 3D set on top measured plus 0.4 percent wall time and plus 8 GB per simulated year. XIOS server rank asynchronous IO is what makes that nearly free. Turn them off for diagnostics style runs that do not want the regridded set. Both need xios.fesom_regular_res_lon, xios.fesom_regular_res_lat and xios.interpolation_order.

Ocean biogeochemistry output gates

Applies to: AWI-ESM3-cc, which is the only setup with REcoM.

file_def_fesom.xml.j2 gates the biogeochemistry file blocks on three switches that mirror the REcoM &parecomsetup logicals, so a block is only enabled when the tracers it wants actually exist:

fesom.recom_enable_3zoo2det
fesom.recom_enable_coccos
fesom.recom_ltra_diag

AWI-ESM3 sets all three from recom_setting, so you normally leave them alone. Their purpose is to stop XIOS writing files that would contain nothing but fill values.

Change the number of vertical levels for pressure level output of OpenIFS

Applies to: AWI-CM3 v3.1 and later, and every AWI-ESM3. AWI-CM3 v3.0 has no IO server.

Output in controlled via XIOS. The pressure levels onto which the data is interpolated from model levels is set in axis_def.xml. In principle two options exist. Changing the number of levels for all 3D pressue level output fields and changing the number of levels only for some output fields.

For all fields

To change the number of layers for all 3D pressure level fields, in axis_def.xml in section <axis_group id="pl_axes" ...> modify n_glo="19" to the new number of layers, value="(0,18) to 0 nlayers-1 and subequently list the pressure levels in Pa.

For select fields

For selective fitting, in the <axis id="pressure_levels_zoom" section, you can make a sub-selection of the levels previously defined in the <axis id="pressure_levels" section. In the existing example three layers are selected: <zoom_axis index="(0,2)[10 11 12]" />. To write a field on this reduced vertical domain you have to define a new grid in grid_def.xml, specifying as domain pressure_levels_zoom instead of pressure_levels. With this new grid you go to file_def.xml and define a new file (copy paste from pressure level output to pressure level output zoom, and select the new grid). Then you delete the variables that should not be written on all levels from the pressure level output and insert them at pressure level output zoom.