The factors of suspended sediment concentration increasing in the Lena River delta

This paper presents an analysis of the factors contributing to the longitudinal increase in suspended sediment along the Lena River delta branches. Satellite images (Landsat 5-9) from 2000 to 2022 during the open channel period from June to September were captured for the suspended sediment concentration modeling. This period coincides with the water discharge in the Lena River ranging from 17,400 to 78,100 m³/s. The ERA5-Land reanalysis, monitoring observations at the Samoilovsky Island research station and remote sensing data were employed to estimate the factors influencing suspended sediment concentration changes. These factors included air temperature, precipitation, wind speed, solar radiation flux, permafrost temperature, water discharge and suspended sediment concentration in the top of the delta top, and the intensity of bank retreat. The results of the correlation analysis indicated that the observed increase in suspended sediment concentration was attributable to a combination of meteorological factors (temperature, precipitation, wind speed, and solar radiation flux) and the intensity of riverbank erosion associated with thermal processes. The longitudinal increase in in suspended sediment concentration (on average for the study period by 2-4% along the delta length) can be explained by an average daily air temperature and permafrost temperature increase. The analysis demonstrated that temperature factors exert a predominant influence on riverbanks comprising the Ice Complex. here was a significant correlation between the rates of riverbank degradation and the concentration of suspended sediment.