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Abstract:
The huge area of the delta located in the permafrost area where current climate changes influence on water regime sediment transport in the delta branches due to aggravate of river bank thermal-erosion and thermal-denudation. According to ERA5-Land reanalysis data significant changes in air temperature were found since 2004, as the trend for the period from 2004 to 2021 increase by +1.89°C/10 years. A significant change of air temperature, precipitation and solar radiation have occurred at the beginning of the XXI century and its changes could activate new factors of suspended sediment sources. Comprehensive suspended sediment dynamics studies along the main channels if the Lena River Delta were identified from the middle of the XIX century to 2022 by bringing together remote sensing and acoustic doppler current profiler techniques, sediment concentration estimates by gravimetric analyses of sediment concentration data during 2022 Lena Delta expedition and previous researches in this area. Results represent long-term and seasonal variability of suspended sediment changes over the delta for the period from 1999 to 2022. The existence of specific drivers — continuous permafrost thaw – influence on the changes of delta islands. Finally, the maps of channel changes were derived to calculate volumes of material exposed to the river due to fluvial processes and possible impact of thermal erosion of permafrost banks. The compiled channel changes map explains possible impact of accelerated hydroclimatic evolution on thermal erosion during 2000 to 2021. These results shine light on the conditions of suspended sediment dynamics of the arctic delta.
