ARL Releases MONET Version 2.2 and MONETIO Version 0.1

March 2020

Model and ObservatioN Evaluation Tool Version 2.2 (MONET v.2.2), released by ARL on March 25, boasts major updates designed to streamline the user experience and facilitate a more robust development environment. Separation of the input/output (I/O) libraries into their own repository, the Model and ObservatioN Evaluation Tool Input and Output v0.1 (MONETIO), was implemented to provide more flexibility for users.


MONET is a python library that enhances functions necessary for meteorological, air quality or climate analysis. Simple statistics, quick viewing of data, regridding and interpolating in time are among its common functions. MONET is accessible on GitHub at and can be installed from the conda-forge feedstock by utilizing: conda install -c conda-forge monet. Related documentation can be found at


MONETIO is ARL’s newest python library. Developed to aid loading and saving of common meteorological and air quality measurements and models, MONETIO leverages the pandas and xarray libraries and provides a common format for use in conjunction with MONET. MONETIO is accessible on Github at and can be installed from the conda-forge feedstock by utilizing: conda install -c conda-forge monetio. Related documentation can be found at

Release notes for MONET v2.2
• Removed extraneous I/O functions and relocated to a new sister repository at (to ensure that MONET remains lean and focused)
• Added pyresample back as the default restructure (since esmpy and xesmf are not available on Windows)
• Added functionality to read common data formats with xarray (e.g. netCDF Climate and Forecast (CF) convention); MONET Accessor options retained
• Added a conversion from cftime to datetime xarray objects
• Fixed the quick_map xarray.DataArray Accessor to ensure compatibility with generic netCDF files in the CF convention
• Added a Pandas Accessor to gain additional functionality for use with surface observational datasets
• Added a function to convert MONETIO dataframes into Little_r formatted lists or Pandas DataFrames for use in METplus
• Removed the hysplitutil directory in preparation for migration to a new repository focused on HYSPLIT
• Implemented bug fixes for accessor functionality

Release notes for MONETIO v0.1
• Launched MONETIO v0.1 with all I/O functionality present in MONET v2.1+; providing a more streamlined interface to access monetio functionality
• Overhauled the icartt module to remove dependence on PsuedonetCDF
• Implemented bug fixes for obs and model functions

Logos for MONET and MONETIO (top and bottom, respectively). Both are the NOAA logo beside the program name in capital letters in blue font with the words AIR RESOURCES LABORATORY underneath it in the same blue font.