EGU24-12905, updated on 09 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

A new ESMValTool metric using point source observations from AeroNET

Catherine Hardacre1, Klaus Zimmermann2, Joakim Löw2, and Jane Mulcahy3
Catherine Hardacre et al.
  • 1School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand
  • 2Swedish Meteorological and Hydrological Institute, Norrköping, Sweden
  • 3Met Office, FitzRoy Road, Exeter, EX1 3PB, UK

ESMValTool is an open-source community-developed diagnostics and performance metrics tool for the evaluation and analysis of Earth System Models (ESMs). Key to model evaluation with ESMValTool is the use of observational data, which must comply with Climate Model Output Rewriter (CMOR) standards. ESMValTool provides methods to generate CMOR compliant datasets, but these are designed to process gridded observational data sets, such as those from satellites, and currently it is more difficult to develop point source datasets. Here we present a new ESMValTool metric for evaluating model output against an observation-based climatology of aerosol optical depth (AOD) from the Aerosol Robotic Network (AeroNET). This metric includes a downloader and formatter to generate CMOR compliant datasets for the observational AOD timeseries from all AeroNET stations. These are collated into a single NetCDF file. A new ESMValTool recipe and diagnostic process and evaluate the model output against the observational AOD dataset at model grid cells co-located with the AeroNET stations. Model output is processed in the recipe using available pre-processers to generate multi-annual seasonal means. The observational AOD timeseries from the AeroNET stations are processed in the diagnostic to generate multi-annual seasonal means, or ‘climatologies’. Because the AOD timeseries from the AeroNET stations can be incomplete, filtering criteria are applied to the data from each station to ensure sufficient temporal coverage according to the user’s requirements. We evaluate AOD at 440mn simulated by CMIP6 historical ensemble members against the AOD climatologies using the new ESMValTool metric. We also demonstrate how changing the filtering criteria can modify the observational climatologies, and thus the evaluation metrics. The new method extends atmospheric composition evaluation in the ESMValTool framework by adding a key aerosol metric. We hope that the techniques used to develop this metric can be applied to other point source observation datasets.

How to cite: Hardacre, C., Zimmermann, K., Löw, J., and Mulcahy, J.: A new ESMValTool metric using point source observations from AeroNET, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12905,, 2024.