Home – Home – Jornals – Geography and Natural Resources 2026 number 2

The article identifies modern features of long-term fluctuations in air temperature for a year as a whole, and for cold (October-April) and warm (May-September) seasons in the Lena River basin with a widespread occurrence of permafrost rocks. It is shown that the increase in temperature during the cold season, which began in the mid-1980s, has had virtually no effect on the river runoff. A more important factor is the increase in temperature during the warm season since the mid-1990s, which promotes a more active participation of suprapermafrost waters (perched water runoff) in the formation of the Lena River runoff. It has been found that the distribution of the average long-term annual runoff across the catchment area is largely determined by the distribution of annual precipitation (correlation coefficient R = 0,8). Long-term fluctuations in the annual river runoff are also largely caused by fluctuations in annual precipitation (R = 0,7-0,9). In recent years (2008-2022), an increase in the runoff has been observed in the middle and lower reaches of the Lena River. Near the villages of Tabaga and Kyusyur, it amounted to 17 and 5 %, respectively, compared to the average runoff for 1930-1980, according to the State Hydrological Institute. In the upper reaches, at the cross-section near the working settlement of Kachug, the runoff, on the contrary, decreased by 6 % compared to the early 1960s. An assessment of the main elements of the genetic vertical structure of the Lena River runoff is given. In recent years, the share of the surface component of the runoff in the total runoff has been 35-50 %. A significant role in the formation of the river runoff in the warm season is played by the runoff of seasonal perched water (suprapermafrost waters) and aufeis, which constitute 20-25 % of the annual total runoff. Sustained groundwater runoff, primarily interpermafrost and subpermafrost water, accounts for 20-40 %.