Physical Oceanography (Dec 2022)
Variability of the Arctic Frontal Zone Characteristics in the Barents and Kara Seas in the First Two Decades of the XXI Century
Abstract
Purpose. The article is devoted to studying the long-term variability of the characteristics of surface manifestations of the Arctic Frontal Zone formed seasonally in the Marginal Ice Zone of the Arctic seas. Methods and Results. To identify the frontal zone, the satellite measurements of surface temperature carried out by the MODIS/Aqua and VIIRS/Suomi NPP from August to September 2002–2020 are used as initial data. The Arctic Frontal Zone position and characteristics were determined using the cluster analysis. In the warm period of the year, the average long-term thermal surface gradient in the Arctic Frontal Zone is revealed to be 0.06 °C/km, and its area – 348,000 km2. Variability of the interannual gradient estimates in this region ranged from 0.04 to 0.09 °C/km, and the area – from 159,000 to 489,000 km2. Conclusions. During the last two decades, spatial position of the frontal zone has been characterized by a significant shift to the north (81°–82°N). The surface temperature in the frontal zone in the last decade was on average higher than that in the previous one. Such dynamics is conditioned by retreat of the arctic ice cover edge. The thermal gradient maximum values in the Arctic Frontal Zone were recorded in 2009, 2016 and 2018 at the significant near-surface wind speeds and the reduced ice cover concentration. The surface temperature, the thermal gradient and the frontal zone area are shown to be conditioned by the ice area and concentration in last year’s autumn season. It is established that during a warm season, the North Atlantic Oscillation winter index governs variation of the surface temperature in the Arctic Frontal Zone.
