INVESTIGATION OF SPATIAL AND TEMPORAL VARIABILITY OF CHLOROPHYLL “A” CONCENTRATION IN THE TSIMLYANSK RESERVOIR USING OLCI SATELLITE IMAGES (2016-2019)
The spatial and temporal distribution of chlorophyll “a” concentration in the Tsimlyansk reservoir in the modern period was analyzed using an algorithm developed at the SSC RAS based on satellite images of the OLCI scanner for the period 2016-2019 and data from field research. The latest data was compared with the period 2003-2012 covered by the MERIS satellite scanner survey. According to satellite imagery in the water area of the Tsimlyansk reservoir for 2003-2012 and2016-2019, two annually recurring peaks of phytoplankton development in the dam and central areas can be distinguished: spring, associated with the bloom of diatoms and summer-autumn, due to the rapid development of blue-green algae. It was found that the seasonal dynamics of chlorophyll a concentration in the central and near-dam areas of the reservoir in the modern period has not undergone significant changes in comparison with 2003-2012. However, in the upper region of the reservoir, the seasonal dynamics of chlorophyll a concentration in the modern period has become very similar to that in the central region. At the same time, the average concentration of chlorophyll a has increased significantly, which may indicate a change in the hydrological regime of the reservoir.