Differences in behavior and distribution of permafrost-related lakes in Central Yakutia and their response to climatic drivers

• Published in: Water Resources Research
• Main Authors: Ulrich, Mathias, Matthes, Heidrun, Schirrmeister, Lutz, Schütze, Juliane, Park, H., Iijima, Yoshihiro, Fedorov, Alexander N.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley 2017
• Subjects: Ice; permafrost; Thermokarst; Yakutia
• Online Access: https://epic.awi.de/id/eprint/44608/; https://epic.awi.de/id/eprint/44608/1/Ulrich_et_al-2017-Water_Resources_Research.pdf; https://hdl.handle.net/10013/epic.50900; https://hdl.handle.net/10013/epic.50900.d001

The Central Yakutian permafrost landscape is rapidly being modified by land use and global warming, but small-scale thermokarst process variability and hydrological conditions are poorly understood. We analyze lake-area changes and thaw subsidence of young thermokarst lakes on ice-complex deposits (yedoma lakes) in comparison to residual lakes in alas basins during the last 70 years for a local study site and we record regional lake size and distribution on different ice-rich permafrost terraces using satellite and historical airborne imagery. Statistical analysis of climatic and ground-temperature data identified driving factors of yedoma- and alas-lake changes. Overall, lake area is larger today than in 1944 but alas-lake levels have oscillated greatly over 70 years, with a mean alas-lake-radius change rate of 1.663.0 m/yr. Anthropogenic disturbance and forest degradation initiated, and climate forced rapid, continuous yedoma-lake growth. The mean yedoma lake-radius change rate equals 1.261.0 m/yr over the whole observation period. Mean thaw subsidence below yedoma lakes is 6.261.4 cm/yr. Multiple regression analysis suggests that winter precipitation, winter temperature, and active-layer properties are primary controllers of area changes in both lake types; summer weather and permafrost conditions additionally influence yedoma-lake growth rates. The main controlling factors of alas-lake changes are unclear due to larger catchment areas and subsurface hydrological conditions. Increasing thermokarst activity is currently linked to older terraces with higher ground-ice contents, but thermokarst activity will likely stay high and wet conditions will persist within the near future in Central Yakutian alas basins.