Dust impact on surface solar radiation levels in Cyprus
Authors: Charalampous Georgia , Fragkos Konstantinos , Marenco Franco , Derimian Yevgeny , Nisantzi Argyro , Mamouri Rodanthi-Elisavet , Pikridas Michalis , El Hajj Danielle , Hadjimitsis Diofantos , Sciare Jean , Kazadzis Stelios 
Published: July 2023

In this study, we analyze the impact of dust on shortwave surface irradiance (global and direct) over a period of five years (2017-2022). We use measurements of global horizontal irradiance (GHI) and direct normal irradiance (DNI) from three stations located in different areas in Cyprus: Agia Marina Xyliatou (35.04N; 33.06E; 535m above sea level), Athalassa (35.14N;33.39E; 158m above sea level) and Larnaca Airport (34.873N; 33.62E; 2m above sea level).
Under clear sky conditions, aerosols are one of the most influential factors on surface solar radiation levels. Aerosols can change surface radiation fluxes by both absorbing and scattering solar radiation. In particular, dust aerosols are known to efficiently absorb solar radiation, especially at lower wavelengths. Cyprus, located in close proximity to both Northern Africa and the Arabian Peninsula, frequently experiences dust events. The island's high number of cloudless days make it an ideal location for studying the radiative effects of dust. Previous studies using satellite based and CAMS related data showed that Aerosols attenuate 5&#8211;10% of the annual global horizontal irradiation and 15&#8211;35% of the annual direct normal irradiation. Dust is responsible for 30&#8211;50% of the overall aerosol attenuation. In addition, optical properties of dust vary, as the origin can be from N. Africa or Middle East. We selected only cloud-free, quality-controlled, excluding any data that fail to pass the BSRN recommended QC tests, measurements for this study.
The dust events are identified using the CIMEL sun-photometers data&#160; from the Aeronet stations in Agia Marina Xyliatou and CUT-TEPAK in Limassol in conjuction with the PollyXT lidar station in Limassol. The origin of the dust airmasses are identified as well by&#160; analyzing the back-trajectories from the Hysplit model. Cloudless and aerosol-free Sky conditions are simulated with the radiative transfer model LibRadtran and the dust radiative effects are estimated as the difference between measured irradiance and the modeled values. This study is important for understanding the impact of dust on surface solar radiation, which has important applications in solar energy production and climate modeling.
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Acknowledgments: &#8220;This research is performed under the auspices of the Memorandum of Understanding between ERASTOTHENES CoE and The Cyprus Institute. The authors acknowledge the &#8216;EXCELSIOR&#8217;: ERATOSTHENES: E&#935;cellence Research Centre for Earth Surveillance and Space-Based Monitoring of the Environment H2020 Widespread Teaming project (www.excelsior2020.eu).The &#8216;EXCELSIOR&#8217; project has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under Grant Agreement No 857510, from the Government of the Republic of Cyprus through the Directorate General for the European Programmes, Coordination and Development and the Cyprus University of Technology&#8221;. This project has also received funding from the European Union&#8217;s Horizon 2020 research and innovation programme under grant agreement No. 856612 and the Cyprus Government (EMME-CARE).