Usage

fremor is the CLI entry point for rewriting climate model output with CMIP-compliant metadata, a process known as “CMORization”. This set of tools leverages the external cmor python API within the FRE ecosystem.

Note

fremor is an independent package extracted from the fre.cmor submodule of fre-cli. The fre cmor subcommand maps directly to fremor:

fre -vv -l logfile.txt cmor run [OPTIONS]   # fre-cli
fremor -vv -l logfile.txt run [OPTIONS]      # fremor

Background

cmor is an acronym for “climate model output rewriter”. The process of rewriting model-specific output files for model intercomparisons (MIPs) using the cmor module is referred to as “CMORizing”.

The fremor tools are designed to work with any MIP project (CMIP6, CMIP6Plus, CMIP7, etc.) by simply changing the table configuration files and controlled vocabulary as appropriate for the target MIP.

Getting Started

fremor provides several subcommands:

  • fremor init — Initialize CMOR resources: generate config templates and fetch MIP tables

  • fremor run — Core engine for rewriting individual directories of netCDF files according to a MIP table

  • fremor yaml — Higher-level tool for processing multiple directories / MIP tables using YAML configuration

  • fremor find — Helper for exploring MIP table configurations for information on a specific variable

  • fremor varlist — Helper for generating variable lists from directories of netCDF files

  • fremor config — Generate a CMOR YAML configuration file from a post-processing directory tree

To see all available subcommands:

fremor --help

Verbosity and Logging

fremor supports multiple verbosity levels and optional log-file output. These flags are global options on the top-level fremor command, so they must appear before the subcommand they modify:

fremor -v run ...                   # INFO level logging
fremor -vv run ...                  # DEBUG level logging
fremor -vvv run ...                 # DDEBUG for large data-structure dumps
fremor -q run ...                   # ERROR level only (quiet)
fremor -l fremor.log run ...        # Append fremor logs to file
fremor --log-file fremor.log run ...  # Same as -l; --log_file also works

  • -v / --verbose is count-based. -v enables INFO, -vv enables DEBUG, and -vvv enables the custom DDEBUG level used for large arrays, dictionaries, and other high-volume data-structure dumps.

  • -q / --quiet forces ERROR logging and overrides any -v flags.

  • -l / --log-file / --log_file appends to the named file while still leaving normal screen output enabled. Place this option before the subcommand; for example, after run the short -l flag belongs to fremor run’s varlist argument instead of the global log-file setting.

CMOR Runtime Logfiles

When fremor run (or a fremor yaml call that dispatches to run) enters the CMOR rewrite path, it gives CMOR a logfile path. If fremor.cmor_constants.CMOR_LOG is set, that explicit path is used; otherwise fremor falls back to a per-file .log path derived from the temporary .nc file being rewritten.

After cmor.close() fully tears down the CMOR module, fremor re-reads that CMOR logfile for INFO-or-more-verbose runs (-v, -vv, -vvv) and forwards each line through the standard fremor logger. It then renames the CMOR logfile to match the produced NetCDF filename (*.nc → *.log), and if the output first landed under CMOR_tmp/, the .log file is moved alongside the final CMORized output file.

Additional Resources