Numerical simulation of permafrost thermal regime and talik development under shallow thaw lakes on the Alaskan Arctic Coastal Plain

Abstract

[1] Thaw lakes are one of the most obvious manifestations of the hydrological system at work in the tundra regions of the Alaskan Arctic Coastal Plain, but the extent of the role of thaw lakes in Arctic land-atmosphere interactions and feedback has yet to be fully understood. This study uses a two-dimensional heat transfer model with phase change under a cylindrical coordinate system to simulate the long-term influence of shallow thaw lakes on the thermal regime of permafrost and talik development on the Alaskan Arctic Coastal Plain. On the basis of previous studies of permafrost and thaw lakes at Barrow, Alaska, a series of simulation cases was conducted using different combinations of long-term mean lake bottom temperature and lake depth. The simulated results indicate that shallow thaw lakes are a significant heat source to permafrost and talik. For a thaw lake with a long-term mean lake bottom temperature of greater than 0.0°C a talik forms under the thaw lake. The maximum talik thicknesses (vertical distance from the ground surface to the permafrost surface) are 28.0, 43.0, and 53.2 m 3000 years after the formation of a shallow thaw lake with long-term mean lake bottom temperatures of 1.0°, 2.0°, and 3.0°C, respectively. Talik development rate is very high in the first several years after a thaw lake formation and decreases gradually with time. No talik forms below a thaw lake with a long-term mean lake bottom temperature equal to or lower than 0.0°C, but the temperature of permafrost below the thaw lake increases with time. Three thousand years after the formation of a thaw lake with a long-term mean lake bottom temperature of greater than or equal to À2.0°C, ground temperature increases of more than 0.5°C occur as far as 300 m from the lake shore and as deep as about 400 m below the ground surface. It is concluded that variation of long-term mean lake bottom temperature has a significant influence on permafrost thermal regime and talik development. Continued monitoring for thaw lake bottom temperature and ground temperature under shallow thaw lakes is needed to further improve the simulation.

Response of seasonal soil freeze depth to climate change across China

“…Numerical modeling studies have shown that snow depth does impact SFD (Zhang and Stamnes, 1998;Ling and Zhang, 2003;Park et al, 2015). Park et al (2015) indicated that both increasing SND and snow structure (e.g., snow density) changes were favorable to soil warming, resulting in active layer thickness decreasing in northern regions as previously found by Frauenfeld et al (2004).…”

Correlation of alpine vegetation degradation and soil nutrient status of permafrost in the source regions of the Yangtze River, China

“…Furthermore, it can contribute to erosion and increase sedimentation and siltation of rivers, which poses additional environmental concerns. Numerical simulation in typical thermokarst lakes in Alaska has shown that the evolution of thermokarst lakes and climate change are closely related, which induces the variation of permafrost in the adjacent thermokarst lakes (Ling and Zhang 2003). The thermokarst process has a significant impact on the ecological environment in permafrost, and it also accelerates the organic decomposition process which can release soluble substances in permafrost, thus affecting the chemical properties of soil mass and surface runoff (Truett and Kertell 1992;Kokelj and Lewkowicz 1999;Kokelj et al 2002).…”

Impacts of shore expansion and catchment characteristics on lacustrine thermokarst records in permafrost lowlands, Alaska Arctic Coastal Plain

“…Most studies have focused on mapping and classifying thermokarst lakes and drained lake basins ( [30,38,78]; Farquharson et al (under review)) or modern lake processes and dynamics. Here, scientific progress was achieved by research on thermokarst lake hydrogeomorphology [6], lake orientation [10,16], geomorphic controls on lake bathymetry [39], lake thermal regimes [13], lake ice regime shifts [5], thermal talik modeling [58], and catastrophic lake drainage [42]. Under scenarios of even modest climate warming, 10-30% of the lowland landscapes of the Arctic Coastal Plain will be affected by thermokarst [46], which could potentially impact the distribution of thermokarst lakes on the landscape.…”