Spatial and temporal stationarity of the Laptev Sea polynyas

The study examines the seasonal and interannual variability of the location and area of flaw polynyas in the Laptev Sea. It utilizes AARI regional charts of ice conditions in SIGRID-3 format covering the years1997 to 2023 as initial data. The analysis is based on an algorithm developed previously for calculating the frequency of occurrence of multiple vector polygon intersections. As a result, monthly charts (fromDecember to May) were created to show the spatial distribution of zones with a 50 % occurrence frequency. The time series of the annual average of this indicator demonstrates a positive trend. The seasonal variations of the polynyas show a distinct pattern: in the first half of the season, the polynyas in the western part of the sea are typically open and wide. However, during spring, the extent of polynyas in the eastern part increases, while those in the western part decrease. This positive trend is observed in both parts of the sea throughout the season, with significant values noted during the spring months (April and May) in the western area. This is particularly important, as the polynya during this period marks the beginning of summer melting, which can have significant implications. By analyzing all polynas polygons from the study period (1997–2023), we identified polygons of recurring polynyas (with a 75% occurrence frequency) and stable polynyas (with a 50 % occurrence frequency). It was discovered that the criterion for recurring polynyas corresponds only to a small section along the fast ice of Teresa Klavens and Thaddeus Bays. Notably, the Western New Siberian polynya has a 50 % occurrence frequency and is located in a narrow strip northwest of Kotelny Island. Previous studies indicate that this section is part of the Great Siberian Polynya; however, it is evident that its development has been limited in recent decades. In contrast, the sections of the Northern-Eastern Taimyr and Anabro-Lena polynyas are significantly larger and exhibit high occurrence frequencies. This scenario may be linked to changes in large-scale atmospheric circulation and the dominance of western circulation patterns.