The ice regime of the northeastern Russia

Abstract

Transport links and provision of hard-to-reach settlements and mining enterprises play an important role in the economic development of the Arctic regions. In winter, winter roads are used as transport arteries; their mode of operation depends on the characteristics of the ice. Winter roads are used in Russia, Canada, USA, Finland, and China. Due to climate warming, the timing of the formation of ice cover on rivers is shifting to later times, and in the spring the ice is destroyed earlier. This could affect the delivery of vital supplies to remote regions. According to recent forecasts, it is assumed that heavy vehicles will not be able to use winter roads by the end of the 21st century. The purpose of the study is to analyze changes in the characteristics of ice cover on the rivers of the Northeast of Russia. To do this, a series of data was collected for the period 1940–2018 on the thickness of the ice cover at 80 hydrological stations located in the basins of the Yana, Indigirka, Kolyma rivers, rivers of the Chukotka Peninsula and the Sea of Okhotsk basin. The catchment areas range from 18.3 to 635,000 km2, and the duration of the continuous series ranges from 2 to 67 years. Three statistical nonparametric tests (Mann-Kendall, Pettitt and Theil-Sen) were used for evaluation. The following characteristics were considered: the maximum ice thickness and the date of its formation, the dates when the ice thickness reached 60 and 90 cm. During the period under review, the maximum ice thickness decreased by an average of 40 cm, while the date of reaching the maximum values remained almost unchanged. The period for the formation of river ice with a thickness of 60 and 90 cm, necessary for the passage of cars and trucks, respectively, has shifted by almost a month. The start date of freeze-up occurs on average 3–4 days later, and the end date of freeze-up occurs 5–8 days earlier. On average, the duration of freeze-up decreased by 5–15 days. The results obtained must be taken into account when drawing up the work schedule for winter roads. This is especially important for regions where communication between populated areas and mining enterprises is possible only through river arteries.