AIFS-COMPO: A Global Data-Driven Atmospheric Composition Forecasting System

Abstract

We introduce AIFS-COMPO, a skilful medium-range data-driven global forecasting system for aerosols and reactive gases. Building on the ECMWF Artificial Intelligence Forecast System (AIFS), AIFS-COMPO employs a transformer-based encoder-processor-decoder architecture to jointly model meteorological and atmospheric composition variables. The model is trained on Copernicus Atmosphere Monitoring Service (CAMS) reanalysis, analysis, and forecast data to learn the coupled dynamics of weather, emissions, transport, and atmospheric chemistry. We evaluate AIFS-COMPO against a range of atmospheric composition observations and compare its performance with the operational CAMS global forecasting system IFS-COMPO. The results show that AIFS-COMPO achieves comparable or improved forecast skill for several key species while requiring only a fraction of the computational resources. Furthermore, the efficiency of the approach enables forecasts beyond the current operational horizon, demonstrating the potential of AI-based systems for fast and accurate global atmospheric composition prediction.

Figures (11)

• Figure 1: A random sample of the day 3 forecast of AIFS-COMPO and IFS-COMPO for total AOD at 550nm.
• Figure 2: AOD prediction performance of IFS-COMPO (red) and AIFS-COMPO (blue) compared against Aeronet observations (yellow). Top left: global RMSE, top right: global bias, bottom left: global temporal correlation, bottom right: a JJA AOD timeseries for North America.
• Figure 3: Comparison of PM predictions for North America, Europe, and China. First row is showing PM$_{2.5}$, second row is showing PM$_{10}$.
• Figure 4: Comparison of NO$_2$, SO$_2$, ozone, and CO predictions of AIFS-COMPO (blue) and IFS-COMPO (red) against observations in North America (first column), Europe (second column), and China (third column).
• Figure 5: Evaluation of ozone profiles. Left: locations of Antarctic stations (top) and North American/European stations (bottom) in white circles. Middle and right: comparison of model predictions, AIFS-COMPO (blue) and IFS-COMP (red) with sonde observations (black). Middle: Using Antarctic stations to capture the ozone hole in September and October, plotted with logarithmic pressure scale. Right: Using all stations of North American/European over a whole year and a linear scale.