Generating scalar diagnostics for a model experiment

The gfdlvitals package supports the generation of scalar diagnostics both embedded within GFDL’s modeling working as well as offline via a command-line interface.

Generating diagnostics through GFDL’s FRE workflow

This is the easiest way to compute the scalar diagnostics. The workflow is designed to calculate the diagnostics during the refineDiag step of the workflow that is called immediately before the post-processing, i.e. frepp stage of the workflow.

The refineDiag_data_stager_globalAve.csh included with the CM4/ESM4-class xmls handles this procedure:

<!-- sample tag to include in xml file -->
<refineDiag script="$(NB_ROOT)/mdt_xml/awg_include/refineDiag/refineDiag_data_stager_globalAve.csh"/>

Generating diagnostics offline

This package includes a script called gfdlvitals that should be present in your path if the installation was successful. The usage of the tool is:

gfdlvitals [-h] [-o OUTDIR] [-m MODELCLASS] [-c COMPONENT]
     [-s STARTYEAR] [-e ENDYEAR] [-g GRIDSPEC] HISTORY DIR

  • -o, outdir: the directory where the SQLite files are written. Default is current directory

  • -m, modelclass: Options include ESM2, CM4. Default is CM4

  • -c, component: Comma-separated list of components to process. Default is all.

  • -s, startyear: Starting year to process. Default is all years.

  • -e, endyear: Ending year to process. Default is all years.

  • -g, gridspec: Path to gridspec tarfile. Used in AMOC calculation. Default is None

  • historydir: Path to directory that contains the history tar files from the model

When specifying a component or list of components, available options are atmos, ice, land, ocean, obgc, and amoc.

Note

The -g or --gridspec option is no longer used. AMOC is generated using the xoverturtning package which relies on grid information contained in the ocean_static.nc file. This option is being retained in the driver, however, since information in the gridspec file might be used to apply angle corrections to the AMOC transports in the future.

AMOC calculation

The Atlantic Meridional Overturning Circulation (AMOC) is calculated using xoverturning. The calculation is available for ocean model version MOM6 or greater. In order to calculate AMOC the following variables are required in the ocean_annual_z output stream:

  • umo

  • vmo

  • geolon

  • geolat

Two AMOC scalars are calculated and added to the globalAveOcean.db file:

  1. amoc_vh: The annual mean maximum overturning streamfunction beteween 20-80N and 500-2500m depth.

  2. amoc_rapid: The annual mean maximum overturning streamfunction at 26.5N between 500-2500m depth.

Note

The xoverturning package has additional options to rotate the transport vectors to true north and to remove the mixed layer thickness flux (uhml/vhml). Neither of these options are used in gfdlvitals.

The scalars above are the y-ward meridional overturning (i.e. msftyyz) based on the residual mean freshwater transport, vmo.