Results of Long-Term Monitoring of the Shelf Water Vertical Thermal Structure at the Black Sea Hydrophysical Polygon of RAS

Abstract

Purpose. The geographical and climatic features of the Crimean Southern coast condition significant dynamic activity of the water thermal structure. Studies of the temperature vertical variability in the absence of the tides’ dominant affect, permit to specify the upwelling structure and dynamics as well as the characteristics of waves of various origin. Such hardly-forecasted processes, the time scales of which constitute from a few minutes to several days can be revealed and registered only by long-term continuous observations. The aim of the study is to analyze the results of long-term monitoring of the thermal processes in the coastal zone near the Crimean Southern coast. It was performed at the Black Sea hydrophysical scientific polygon. Methods and Results. In December, 2012 the observation system for operational control of the water temperature vertical distribution was installed at the stationary platform located in the coastal zone of the Black Sea (the Blue Bay) at a distance of ~450 m from the coast. The sea depth under the platform was ~30 m. Digital temperature sensors having precision better than 0.1 °C were installed with 1.5 m intervals in the temperature string of the system. The profiling period was 60 s. The 6.5 year-long experiment with the observation system provided statistically significant and duration-unique serious of data on variability of the thermal processes in the sea coastal region. By early April 2019, the total duration of the system productive functioning was ~900 days. During this period, more than 1300000 temperature profiles were obtained. Based on the data obtained in 2013, the estimates of a seasonal cycle of the temperature synoptic variability are represented. The upwelling events not related to the wind impact are considered. Conclusions. The long-term data series resulted from the multi-year experiment permit not only to specify, but also to change some of the existing ideas of the thermal processes’ evolution features in shelf zone of the Black Sea. Noted is the expediency of applying the observation system as a segment of the constantly operating network at the coastal polygons for performing hydrophysical measurements in the Black Sea.