How well do climate models represent dust events over the Mediterranean, North Africa, and the Middle East?

Dust aerosols constitute a key component of the Earth–atmosphere system, affecting the radiation budget, the microphysical and optical properties of clouds, air quality, terrestrial and aquatic processes, and human health. Dust-related impacts are critically governed by the atmospheric load of mineral particles and are amplified when the dust burden substantially exceeds background levels. Such conditions, commonly referred to as episodes or events, are exceptional and characterized by pronounced spatiotemporal heterogeneity.

In this study, we present an intercomparison of three state-of-the-art climate models (EC-Earth3, CESM2, and NorESM2) and the GiOcean Reanalysis in representing dust events over the Mediterranean, North Africa, and the Middle East during the period 2003–2018. A percentile-based threshold methodology is applied to  daily dust optical depth (DOD) and aerosol optical depth (AOD) values, at both the grid-cell and regional scales, to identify three intensity-based episode categories: weak, moderate and extreme.  In addition, the satellite-based MIDAS dataset, which provides columnar DOD at 550 nm, is used as a reference for model evaluation.

The primary objective of this study is to assess inter-model differences in the representation of dust episode frequency of occurrence and intensity across multiple spatiotemporal scales, considering both free-running and nudged model configurations. Our working framework enables a comprehensive analysis by: (i) evaluating the ability of state-of-the-art climate models to represent different dust episode regimes, and (ii) investigating how threshold definitions influence the resulting spatiotemporal patterns of dust episodes. Finally, the outcomes of this study are expected to substantially enhance understanding of the strengths and limitations of climate models in depicting dust episode characteristics, thereby supporting improved projections under different climate scenarios throughout the 21^st century.