1. Shokurova I. G.
   
   Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation (ru)
2. Plastun T. V.
   
   Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation (ru)
3. Kasianenko T. E.
   
   Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation (ru)
4. Stanichnaya R. R.
   
   Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation (ru)
5. Крашенинникова С. Б. (Krasheninnikova S. B.)
6. Simonova Yu. V.
   
   Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation (ru)

Purpose. The study is purposed at analyzing frequency, speed and duration of the alongshore winds inducing the Ekman upwelling near the Southern Coast of Crimea.

Methods and Results. The 6-hour data on the wind speed components at the 10 m height derived from the ERA5 atmospheric reanalysis for 1979–2021, as well as the data of temperature monitoring performed at the Black Sea hydrophysical sub-satellite polygon of Marine Hydrophysical Institute, Russian Academy of Sciences, are used. Frequency and speed of the winds (namely, the southwestern, western and northwestern ones) favorable for development of upwelling near the Southern Coast of Crimea are considered. The multi-year data based calculations show that the seasonal variability in frequency of each of these winds is of an individual character, whereas their average speeds change the same decreasing from winter to summer. In summer, frequency of the western and northwestern winds increases, and that of the southwestern ones – decreases. The total frequency of favorable winds is the highest in June (maximum values), July, January and December. The lowest frequency values occur in August and October. The interannual changes in speed and frequency of the westerly directions winds result in changes in the upwelling numbers and durations. A significant positive relationship was obtained between the mean speed and frequency of these winds in June and the number of upwellings recorded by a water temperature decrease. The correlation coefficients were 0.74 and 0.68, respectively.

Conclusions. The wind conditions for arising of upwelling near the Southern Coast of Crimea are observed in all the months of a year, but the most favorable ones – in June, July, December and January due to the high frequency of westerly winds. High wind speed is also a significant factor for the development of upwelling.