Scientists of Marine Hydrophysical Institute of the Russian Academy of Sciences studied coastal upwellings in the Black Sea, revealing their complex structure and formation mechanisms. The research results were published in the international scientific journal Continental Shelf Research.
Upwellings are areas of rising deep cold waters near the coast, where the water temperature can drop sharply even in the height of summer. For example, off the Crimea coast in summer the temperature can suddenly drop from 25°C to 10°C. This phenomenon has a significant impact on the climate of coastal areas, the marine ecosystem and the tourism industry.
Upwellings were previously thought to be caused primarily by winds pushing warm surface water away from the coast. A new study, based on the analysis of highly detailed satellite images and numerical simulation, has shown that the formation and evolution of upwellings is influenced by a whole range of factors that create their complex spatial structure.
"Our study shows that an upwelling zone can have a very complex shape, since upwelling strength and duration are significantly affected by other factors. For example, ocean eddies can cause additional stretching of the upper warm layer. In their contact zone with the coast, upwellings will occur earlier and temperature will decrease faster," comments the first author of the paper, FSBSI FRC MHI Deputy Director for Research, Doctor of Physical and Mathematical Sciences Arseniy Kubryakov.
Scientists have also found that when upwellings interact with river waters, density differences increase sharply, which leads to intensification of currents and additional cooling of waters in such areas. Moreover, upwellings themselves can significantly affect the surrounding dynamics: powerful currents form on their periphery, which can become unstable and turn into small but extremely intense eddies that capture and transport matter from the shore over long distances.
The study was carried out using advanced data analysis and modeling techniques. The scientists used highly detailed satellite images and performed numerical simulation using modern oceanographic models. This allowed obtaining a detailed picture of the structure and dynamics of the Black Sea upwellings for the first time.
“The applied value of our work lies in the further possibility of increasing the quality of forecasting such phenomena that have a significant impact on comfort and tourism activities, on the region bioproductivity and the oxygen supply to the lower layers of the Black Sea,” emphasizes the author of the study.
The results obtained expand the understanding of fundamental processes in coastal waters and have important practical implications for the development of coastal regions and the conservation of marine ecosystems.
The work will be followed by study of frontal zones on the upwelling periphery using ship observation data.
"This will allow us to clarify the structural features in these dynamically complex areas. We will also work on developing numerical models to achieve even higher resolution when modeling these processes," the scientist shared.
This work was funded by a grant from the Ministry of Education and Science of the Russian Federation “The Southern Vector of National Security in the Context of Geopolitical and Climate Challenges” and within the framework of the state assignment “Analysis, Diagnosis and Operational Forecast of the State of Hydrophysical and Hydrochemical Fields of Marine Waters Based on Mathematical Modeling using Data from Remote and Contact Measurement Methods”.