Quasi-periodic features of the inter-annual and inter-decadal spatial-temporal variability of the wind speed absolute value (W) in the Black Sea area are assessed based on a series of 60-100-year-long direct observations performed at eight coastal stations, and also on the reanalysis data obtained from the NDP-048, WDC, NCDC, NCEP/NCAR (1948) and MERRA (1980-2015 arrays. Three groups of oscillations with the periods T about 60-90, 20-40 and 3-15 years that present in the W direct data are shown by means of the wavelet analysis. As for long-period oscillations (Т ~ 60-90 years), possible relations of such quasi-periodicity with the phases of the North Atlantic Oscillation index characterizing the atmospheric circulation features are investigated. Calculated according to the MERRA array reanalysis, the mean anomalies of January -February average W series separately for groups of years with the values of the NAO index > +1 and <-1 demonstrated in their dynamics the values of different signs for the same Black Sea areas. It is revealed that during the periods when the index positive phase is mainly predominant, the W positive anomaly is formed over the southwestern, south-eastern and eastern parts of the sea adjacent to the coast at a distance 20-100 km from it, and the W negative anomaly -over the rest of the sea. During the years when the index phase is mainly negative, the signs of the W anomalies over almost the same regions change to the opposite ones. IntroductionClimate variability study and prediction are among the most important tasks of Earth sciences being of high applied significance [1,2]. To diagnose and predict the Black Sea condition, the parameters of the wind regime are used, since the tangential wind stress directly affects the sea waves, circulation and mixing of water and indirectly -the thermal and water balance.Main results of wind research in the Black Sea area are presented in [3,4]. They showed the presence of significant negative linear trends in the series of mean annual wind speeds and the frequency of storms in the 20 th century. In [4] it was noted that since the beginning of the 2000s, there was a tendency to increase the frequency of storm winds practically at all hydrometeorological stations. However, the study of the cyclicity of these processes was almost neglected.Search and study of the wind regularities in the inter-annual variability and their relations with the quasi-periodicity of macro-circulation processes in the atmosphere have been still insufficiently developed [5,6]. Therefore, the research of long-term trends in variation of the wind conditions is one of the most important practical tasks in studying the wind field variability in the Black Sea area.
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