Assessing the Pur River freeze-thaw cycles to determine the length of its navigation season

Objective: to analyze the spatiotemporal dynamics of ice-thaw cycles on the Pur River, contrasting the upper reach (Tarko-Sale) with the lower reach (Samburg), in order to identify patterns and trends relevant to climate change. Methods: long-term records of 1937-2024 of ice onset and breakup dates were analyzed using statistical techniques. Geographical and hydrological parameters of the observation sites were incorporated to account for intersite observation points. Results: On average, the ice period in the lower reach (Samburg) is 15-20 days longer than that in the upper reach (Tarko-Sale), a difference linked to stronger river flow and greater Arctic climate influence. A persistent shortening of the river ice season has been detected, with the trend becoming particularly pronounced since 2000. At the same time, a spatial gradient between the upper and lower reaches persists despite the overall warming. Practical significance: the study’s practical value lies in the potential application of the obtained data to predict the ice season, which is important for planning shipping, infrastructure projects and assessing environmental risks in the Arctic zone. The findings also advance the understanding of how northern rivers react to climate change.