DETERMINATION OF THE SEASONAL COURSE AND TRENDS OF THE DISSOLVED OXYGEN CONCENTRATION AND TEMPERATURE IN THE UPPER LAYER OF A DEEP WATER PART OF THE BLACK SEA ACCORDING TO MODERN DATA
Based on archival oceanographic databank of Natural and Technical Systems, the intra-annual variability was analyzed for the dissolved oxygen content and temperatures in the 0 - 150 m layer of the deep-water part of the Black Sea from 1923 to 2020. It was confirmed that in the upper mixed layer the concentration of dissolved oxygen reaches a maximum in March-April, and a minimum in August. The amplitude of the seasonal course decreases with depth and at a horizon of 150 m it falls almost to the noise level. In principle, the seasonal course of oxygen, consistent with intra-annual changes in temperature, has not changed over an almost century period of observation. At the same time, the amplitude-phase characteristics significantly change under the influence of climatic variations. The intermediate layer on the scales of several decades is characterized by a decrease in oxygen and an increase in temperature, which have continued in recent years.