Spectral optical properties of aerosols in Athens, Greece during the August 2021 wildfires and their effects on surface solar radiation

<p>Multiple wildfire episodes have been observed in Greece during August 2021, after a historic heatwave, with temperatures exceeding 45&#176;C. Two of the most destructive wildfires were in Attica and Euboea with smoke plumes covering the city of Athens and affecting significantly not only the air-quality and also the levels of surface solar radiation. During these events, spectral optical properties of aerosols were measured at NOA&#8217;s actinometric platform in Athens, Greece (Thissio site: 23.7&#176;E, 37.6&#176;N) by a CIMEL sun-photometer, and are analyzed in the context of this study. Measurements from a lidar ceilometer, satellite images, and back-trajectories are also used to identify the origin of aerosols during the smoke, but also combined dust and smoke events in low-aerosol days in the same month. Spectral measurements of the direct and diffuse solar irradiance from the Precision Solar Spectroradiometer (PSR) and measurements of the global and diffuse irradiance from precision pyranometers were also available in Athens, used to investigate the effects of different aerosol types on the levels of surface solar radiation measured. Furthermore, the efficiency of the nowcasting and forecasting tool nextSENSE, used to simulate and predict the levels of surface solar radiation, has been evaluated under such conditions.</p><p><strong>Acknowledgements</strong></p><p>This study was funded by the EuroGEO e-shape (grant agreement No 820852) and the H.F.R.I. National Research Project ASPIRE (project number 300).</p>