How are CALIOPE air quality forecasts generated?

To produce air quality forecasts, the CALIOPE modelling system uses and combines different models to estimate anthropogenic and biogenic emissions, as well as atmospheric and weather conditions:

1. WRFv3.5.1
   The Weather Research and Forecasting Model (WRF) is an open-source numerical weather prediction model that simulates meteorological conditions, such as wind, temperature, and vertical mixing. The software is the default meteorological driver of CALIOPE and is supported and maintained by the National Center for Atmospheric Research (USA).
2. CMAQv5.0.2
   The Community Multiscale Air Quality Modeling System (CMAQ) is an offline and open-source atmospheric chemistry transport model used to predict the diffusion of chemical species influencing weather and atmospheric processes. CMAQ is supported and distributed by the Community Modeling and Analysis System (CMAS) Center.
3. HERMESv3
   The High-Elective Resolution Modelling Emission System (HERMES) is an open-source and multi-scale atmospheric emission modelling framework that computes anthropogenic gaseous and aerosol emissions for use in atmospheric chemistry models. The model is supported and maintained by the BSC-CNS. The Model of Emissions of Gases and Aerosols from Nature (MEGAN), which is supported and maintained by the University of California, Irvine (UCI), is implemented in the HERMES code for the estimation of the biogenic emissions from terrestrial ecosystems. 
4. MONARCHv2.0 

The Multiscale Online Nonhydrostatic AtmospheRe CHemistry model (MONARCH) is an advanced chemistry and aerosol modelling system representing the atmospheric chemistry cycle, including emission, transport, and deposition along with aerosol–radiation interactions. The dust component simulates and predicts the dust cycle in the atmosphere with the aim of estimating desert dust's contribution to aerosol diffusion. The BSC-CNS supports and maintains the model and provides operational dust forecasts for the World Meteorological Organization Barcelona Dust Regional Center. Since September 2023, MONARCHv2.0 dust forecasts have replaced the previous BSC-DREAM system to represent the dust component in the CALIOPE system.

Note:
For its regional calculations, CALIOPE is initialised using global meteorological data from the Global Forecasting System (GFS) model of the National Centre for Environmental Prediction (NCEP), while boundary conditions for pollutants and aerosols come from the CAMS Global atmospheric composition forecast, operated by the European Centre for Medium-Range Weather Forecasts (ECMWF).