Impact of climate change on atmospheric circulation, wind characteristics and wave in the western part of the Black Sea

This study reveals changes in atmospheric circulation over the western part of the Black Sea during the period 1979-2019 and related changes in wind conditions and sea wave in the active tourist season, which at the Bulgarian coast spans from June to September. Statistical methods such as linear regression and Spearman's correlation are used. There has been a significant increase in the number of cases with wind from the northeastern quarter of the horizon. The velocity of the wind from this direction has also increased. This has led to an increase in the wave. Spatially, southernmost regions have higher frequency of northeasterly wind. The velocity of the wind from the northeastern quarter of the horizon and corresponding significant wave height show lowest values in June, which gradually increase toward September. The most significant changes in the studied elements are observed in August and September. The causes for these changes are the change in atmospheric circulation, expressed in the north-northeastward shift of the Azores High, which thus exerts a greater impact on the western part of the Black Sea in the active tourist season. The rise of sea level pressure north of the Black Sea along with the low pressure south of it increases the horizontal baric gradient, which leads to stronger and more frequent northeasterly winds. The main economic activity affected by these trends is tourism. Revealed tendencies in the studied climatic elements and SWH in the last decades represent an immediate threat and an obstacle to the development of tourism along the Bulgarian Black Sea coast.

Automated summary

This study reveals changes in atmospheric circulation and wind conditions over the western part of the Black Sea from 1979 to 2019, impacting the active tourist season in Bulgaria from June to September. The increase in wind from the northeastern quarter has led to higher sea waves, with the most significant changes observed in August and September. These trends pose an immediate threat to tourism development along the Bulgarian Black Sea coast.