Study of the North Atlantic Oscillation Influence on the Climate of Europe and Balkan Peninsula

Numerous climate studies have shown that the North Atlantic Oscillation (NAO) has a significant influence on weather conditions in Europe. Regarding the impact of the NAO on the climatic variables over the Balkans, there is a divergence of opinions among contemporary publications. The contradictory results can be attributed to several factors that make the climate of the region complex and multifaceted. This research focuses on the analysis of surface pressure and wind variability at 850 hPa, as a function of the sign and value of the NAO index, in a dense network of data provided by ERA 5, for the period 1940–2023. Using an artificial neural network, we show that: (i) the high sensitivity of northwestern Europe and the Mediterranean to NAO values is confirmed by our analysis; (ii) the impact of moderately negative NAO values is small in the Balkan region; (iii) the NAO values below the 2σ level have a significant impact on the Balkan Peninsula, due to the activation of Mediterranean cyclones.