Impacts of three severe storms on Aegean Sea oceanography (2018-2020)

This study presents a comprehensive analysis of the impacts of severe storms on the oceanography of the Aegean Sea, with specific focus on storms occurring on 15 November 2018, 14 September 2019, and 7 January 2020. Notable changes in oceanographic variables are observed on the storm day and in the subsequent days, gradually returning to pre-storm conditions. During storms, Aegean Sea surface temperatures were 2-3 degrees C below average, with cooling particularly evident along the west coast and northern part. Salinity increases of 0.5-1 PSU are observed during storms, with the most significant effects noted on 7 January. Storms consistently led to a decrease in sea level in our study area, with the western coast and north Aegean Sea experiencing levels 6-10 cm lower than the monthly average. Surface currents along the west coast and within latitudes 36-40 degrees are 0.3 to 0.4 m/s stronger than average during storms. Storm-induced changes in the Thracian Sea's anticyclonic gyre on 5 January reveal a speed increase of 0.3-0.4 m/s. Notably, both temperature and salinity fluxes exhibit significant changes during storms, characterized by a shift from east-to-west transport, contrasting with the west-to-east pattern observed before the storms. This shift is mainly influenced by Ekman transport, which predominantly directs water westward and north-westward when the wind comes from the northeast to southwest. Storms contribute to heightened salinity, increased kinetic energy, and enhanced transport, accompanied by a decrease in temperature, with the most pronounced effects near the surface along vertical layers.