Present and Future Changes in Winter Cyclonic Activity in the Mediterranean–Black Sea Region in the 21st Century Based on an Ensemble of CMIP6 Models

Abstract

A better understanding of expected future cyclonic activity, especially in winter in the Mediterranean basin, is essential in developing scientifically based adaptation and mitigation methods to study extreme precipitation and wind anomalies. The aim of this study was to analyze the changes in winter cyclonic activity in the Mediterranean–Black Sea region, as part of the North Atlantic–European sector, at three 15 year periods: the beginning, middle, and end of the 21st century. Our projections were based on an ensemble of seven Coupled Model Intercomparison Project (CMIP), phase 6, models, which showed the best agreement with NCEP/NCAR and ERA5 reanalyses under the intermediate SSP2-4.5 and highest-emission SSP5-8.5 scenarios. The results showed a consistent increase in the frequency of cyclones over Central Europe and the British Isles, which was associated with shifts in cyclone tracks: northward from the western Mediterranean region and southward from the Icelandic Low region. The latter shift led to a decrease in the frequency in the northern Atlantic–European region. At the same time, there was a reduction in the frequency of cyclones over the eastern region of the Mediterranean Sea, consistent with the decrease in cyclogenesis events. Area-averaged cyclone numbers in the western and eastern Mediterranean and Black Sea subregions reduced at the end of the century under the highest-emission scenario, but not constantly. There was a rise in the middle of the 21st century under both scenarios, which may be linked to long-term multidecadal variability or regional features. In general, our study showed that the future winter cyclonic activity in the Mediterranean–Black Sea region will respond unevenly to global climate changes, due to regional and monthly features and long-term quasiperiodic variability.