SPATIAL AND TEMPORAL VARIABILITY OF THE POLAR FRONTAL ZONE CHARACTERISTICS IN THE BARENTS SEA IN THE FIRST TWO DECADES OF THE XXI CENTURY

Konik A.A., Zimin A.V., Kozlov I.E.

The article considers the spatial and temporal variability of the Polar Frontal Zone (PFZ) characteristics in the Barents Sea during the warm season from 2002 to 2020. In addition, the occurrence of small eddy structures in the PFZ region in different years is investigated, and the relationship of the characteristics of the frontal zone with global atmospheric processes is described. The position and characteristics of the PFZ were derived from satellite measurements using the cluster analysis method. Eddy structures in the PFZ region were detected from images of Envisat Asar and Sentinel‐1A/B synthetic aperture radars. The NAO, EA, EA/WR and SCAND indices were used to assess the influence of atmospheric processes on the PFZ properties. It was found that the intra-annual values of temperature and salinity gradients in the PFZ region remained stable during the warm season and reached 0.05 °C/km and 0.02 ‰/km, respectively. The variability of the interannual estimates of the PFZ properties ranged from 0.02 °C/km to 0.08 °C/km in temperature, from 0.01 to 0.03 ‰/km in salinity, and from 120,000 to 425,000 km2 in area. The maximum monthly mean values of the PFZ area were observed in 2007, while the minimum — in 2003. The obtained results clearly showed that the intensity of the PFZ decreased after 2010, which is presumably related to the “Atlantification” of the Barents Sea. The maximum number of small eddy structures in the PFZ region was identified in 2009. It is shown that the SCAND index for the previous winter season can be used as a predictor for predicting the characteristics of the PFZ in the summer period.

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