The variability of ice conditions along the Northern sea route for the period 1997–2018

The paper discusses the methodology and results of electronic ice charts processing.The charts taken from AARI archive.The Barents, Kara, Laptev, East Siberian and Chukchi seas Ice maps refl ect ice conditions for the period from 1997 to 2018 for the April-May inter-annual interval.The total stage lengths of «Sabetta -the Kara Gate -Murmansk» and «Sabetta -the Vilkitski Strait -the Bering Strait» standard routes were calculated at certain conditions of ice navigation.The route "Sabetta -the Bering Strait" was divided into sections within the Kara sea, Laptev Sea, East Siberian and Chukchi Seas for analysis.The purpose of the study is to obtain the values of the length of the routes in different categories of ice and to analyze changes trend of navigation in ice conditions for the period 1997-2018.The series were checked for the presence of trends using the integral curves method.The homogeneity of the series was checked using Wilcoxon -Mann-Whitney and Siegel -Tukey rank non-parametric criteria.Most of the series proved to be non-homogeneous.The following