Dust aerosol radiative effects during a dust event and heatwave in summer 2019 simulated with a regional climate model over Spain

This study investigates the radiative effects of dust aerosols in the Mediterranean region during a dust event accompanied by a heatwave in summer 2019, using the ALADIN-Climate regional climate model developed at Centre National de Recherches Météorologiques. An evaluation of the simulations performed by ALADIN-Climate is made, showing its ability to reproduce the variability of this dust event. For example, the aerosol optical depth and the shortwave (SW) downward radiative flux at bottom-of-the-atmosphere are compared against observations. Therefore, the dust direct and semi-direct radiative forcings (DRF, SDRF) of dust aerosols provided by ALADIN-Climate model are analyzed at the top-of-the-atmosphere, resulting in a DRF of -0.79±0.76 (+0.14±0.07) W/m2 and SDRF of +1.27±1.34 (+0.22±0.45) W/m2 in SW (LW) over Spain. Finally, the changes in the state of the atmosphere associated with the dust aerosols are estimated, showing an increase of atmospheric stability and a possible role of the dust particles as cloud condensation nuclei.