ГИДРОМЕТЕОРОЛОГИЧЕСКИЕ ФАКТОРЫ И ИХ ВЛИЯНИЕ НА СОДЕРЖАНИЕ ХЛОРОФИЛЛА-α В АЗОВСКОМ МОРЕ В 2006–2022 ГГ.

Abstract

Background. Chlorophyll-α concentration is a key environmental parameter used to calculate the primary production of a water body, which, in turn, determines phytoplankton biomass. The fields with increased chlorophyll concentration can develop under the influence of various hydrometeorological factors considered in this work, such as air and water temperatures, cloud amount, wind-driven water mixing, and precipitation affecting the surface water layer. Relevance. Monitoring of chlorophyll distribution as it is influenced by hydrometeorological factors facilitates the rational fisheries management on account of their relation to the phytoplankton biomass providing fish and zooplankton with a food source. The aim of this work is to analyze the inter-annual variability of the average monthly hydrometeorological factors and their influence on the chlorophyll-α concentration in the Azov Sea (excluding Taganrog Bay) for the time range from 2006 to 2022. Methods. Spatial and temporal analysis of the average monthly water temperatures and chlorophyll-α concentrations has been conducted based on the daily satellite images of the sea surface taken by MODIS spectroradiometer in the Azov Sea; the analysis of the meteorological characteristics has been carried out using the weather observation data from international data exchange and reports (SYNOP, METAR) posted on the website pogodaiklimat.ru for the time range from April 2006 to September 2022. Results. It is shown that, for the entire investigated time range (2006–2022), the trends of the inter-annual variability of the average monthly air and water temperatures were not significant. An increase in water temperature that started in the middle of 1990s changed for the opposite in 2011, i. e. turned into a decrease. The wind velocity above the Azov Sea (excluding Taganrog Bay) over the investigated time range gradually decreased, which fell in line with the decrease in the chlorophyll-α concentrations. The average monthly cloud amount in the area has shown a weak inter- annual and considerable seasonal variability with relatively low values in the summer season and high values in the winter season. A positive trend of the monthly amount of atmospheric precipitation was observed, in contrast with the negative trend of the chlorophyll-α concentration. Conclusion. A significant positive correlation of the average monthly chlorophyll-α values with water and air temperatures has been identified, as well as a negative one with the wind velocity and cloud amount over the Azov Sea (excluding Taganrog Bay) — both in the individual investigated areas and in the sea as a whole.