Twenty-First-Century Changes in the Eastern Mediterranean Etesians and Associated Midlatitude Atmospheric Circulation

The Etesians are the dominant synoptically driven winds observed in the Eastern Mediterranean, usually from late spring to late summer. Due to the complex topography, the Etesians can be very strong and pose significant environmental hazards, especially over wildfire incidents. This study assesses the impacts of climate change on future Etesians by analyzing the response of the most recent EURO-CORDEX regional climate simulations at the 12-km grid resolution over the twenty-first century. The mean model ensemble projects a significant increase of the Etesians' frequency and intensity under the two emission scenarios RCP4.5 and RCP8.5. This response is connected to an increase in the zonal wind at 200 hPa, a reinforcement of the midlatitude westerly flow, and a decrease in the wave amplitude. These circulation changes accelerate the mid-to-high latitude eastward propagation of the large-scale circulation systems which can favor enhanced ridges over the Balkans. A strengthening and poleward shift of the subtropical jet stream is also projected, connected with stronger subsidence over the Eastern Mediterranean. The projected changes will have profound environmental and societal implications, including the lengthening of the wildfire season and increasing air pollution risk in the region. On the other hand, the current estimate of future wind power potential in the Aegean Sea will be significantly increased by the end of the century, which might have positive impact in the regional economy.