MELODIES MONET aims to help researchers systematically and reproducibly compare global and regional atmospheric chemistry model output with measurements and/or other models. It aims to overcome several challenges, including providing access to the complex atmospheric chemistry datasets (numerous compounds with complex, non-standardized names, various time and spatial sampling, different instruments and platforms), as well as routines to extract model results at appropriate time and spatial resolutions to quantitatively compare to the observations. Currently MELODIES MONET provides an initial structure that we hope well grow into a comprehensive analysis package in the future. Our goals are:

  • Well documented for easy use by the community

  • Written to be user-friendly with easy customization

  • Written in open-source programming languages, mainly Python

  • Publicly available through GitHub:

  • Keep the code and structure of MELODIES MONET simple and easy to understand in order to encourage the community development of the code

  • Maintain capabilities to produce hundreds of plots for quick diagnostic assessments while also being flexible enough to produce publication quality plots

Connection with NOAA’s MONET

At the same time that a need for MELODIES was identified, NOAA was developing a tool to be used for the automated comparison of model forecasts and measurements at ground stations in the USA. Thus, the Model and ObservatioN Evaluation Toolkit (MONET) was created (Baker and Pan, 2017). The usefulness for the broader community was quickly realized and the clear overlap between the two projects allowed collaboration between NCAR and NOAA and the creation of the MELODIES MONET project.

MONET specifically encompasses two packages:

  • MONET I/O package that focuses on importing and exporting model and observational data into the necessary formats for further analysis (, and

  • MONET base package that sets up universal functions such as re-gridding and nearest neighbor calculations (

The two MONET packages above are used by MELODIES MONET to complete analysis and plotting. Most users will only need to work with the MELODIES MONET code-set to complete their desired analysis.

diagram showing connections between MONET, MONETIO and MELODIES MONET

The structure and function of MONET and MONET I/O, and MELODIES MONET interaction. Adapted and updated from Figure 1 in Baker and Pan (2017).