Ponding vs. baydzherakh formation on Yedoma uplands: Implications for modern thermokarst development and thaw subsidence in North Yakutia

• Main Authors: Günther, Frank, Grosse, Guido, Veremeeva, Alexandra, Maximov, Georgy
• Format: Conference Object
• Language: unknown
• Published: 2016
• Subjects: Active layer thickness; Ice; permafrost; Thermokarst; Tundra; Yakutia; Siberia
• Online Access: https://epic.awi.de/id/eprint/42591/; https://epic.awi.de/id/eprint/42591/1/ICOP_2016_Book-of-Abstracts_858.pdf; https://hdl.handle.net/10013/epic.49208; https://hdl.handle.net/10013/epic.49208.d001

Permafrost landscapes of Northern Yakutia recently experienced a widespread warming of mean annual air temperatures and mean positive daily air temperatures during the arctic summer (Federov et al, 2014). Especially in the tundra zone this has led to increased active layer thickness (ALT) and suggests that thermokarst processes reactivate or intensify. However, particularly in the light of the enormous area underlain by ice and carbon-rich permafrost, still only few observations of permafrost-thaw related landscape dynamics exist. Permafrost degradation has consequences for local hydrology, ecosystems, biogeochemical cycling, and sometimes communities. For example in East Siberia, widespread and irreversible thaw subsidence of up to 11 cm per year has been detected on the arctic island Muostakh (Günther et al., 2015), where coastal erosion at average rates of 1.8 m/yr has not only reduced the island’s area by 25% over more than 60 years, but also provides a constant renewal of the erosional base. In this case, favorable drainage conditions provide the prerequisite for active layer thickness deepening during warm summers, when ground ice stability thresholds are exceeded and ground ice thaw and subsequent terrain lowering take place. Our combined approach of ground-based ALT measurements and remote sensing-derived observations of elevation change revealed an inverse connection of shallow seasonal thaw and strong long-term subsidence, which is related to the minimum depth where permafrost thaw encounters pure ground ice bodies. In this study, we focus not only on monitoring thermokarst and subsidence, but also aim to find commonalities and differences of change or no change on yedoma uplands, slopes, and thaw depressions on the landscape scale using multi-temporal digital elevation models (DEMs) from historical aerial photographies, modern satellite stereo imagery, and on-site repeat laser scanning campaigns. In this context, a best practice strategy for remote sensing data fusion combining 2D and 3D information ...