Articles | Volume 8, issue 3
The Cryosphere, 8, 815–826, 2014
The Cryosphere, 8, 815–826, 2014

Research article 05 May 2014

Research article | 05 May 2014

Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska

L. Liu*,1, K. Schaefer2, A. Gusmeroli3, G. Grosse4, B. M. Jones5, T. Zhang6,2, A. D. Parsekian1,***, and H. A. Zebker1 L. Liu et al.
  • 1Department of Geophysics, Stanford University, California, USA
  • 2National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences,
    University of Colorado at Boulder, Colorado, USA
  • 3International Arctic Research Center, University of Alaska Fairbanks, Alaska, USA
  • 4Geophysical Institute, University of Alaska Fairbanks, Alaska, USA
  • 5Alaska Science Center, US Geological Survey, Anchorage, Alaska, USA
  • 6Ministry of Education Key Laboratory of West China's Environmental System, Lanzhou University, China
  • *now at: Earth System Science Programme, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
  • **now at: Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
  • ***now at: Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming, USA

Abstract. Drained thermokarst lake basins (DTLBs) are ubiquitous landforms on Arctic tundra lowland. Their dynamic states are seldom investigated, despite their importance for landscape stability, hydrology, nutrient fluxes, and carbon cycling. Here we report results based on high-resolution Interferometric Synthetic Aperture Radar (InSAR) measurements using space-borne data for a study area located on the North Slope of Alaska near Prudhoe Bay, where we focus on the seasonal thaw settlement within DTLBs, averaged between 2006 and 2010. The majority (14) of the 18 DTLBs in the study area exhibited seasonal thaw settlement of 3–4 cm. However, four of the DTLBs examined exceeded 4 cm of thaw settlement, with one basin experiencing up to 12 cm. Combining the InSAR observations with the in situ active layer thickness measured using ground penetrating radar and mechanical probing, we calculated thaw strain, an index of thaw settlement strength along a transect across the basin that underwent large thaw settlement. We found thaw strains of 10–35% at the basin center, suggesting the seasonal melting of ground ice as a possible mechanism for the large settlement. These findings emphasize the dynamic nature of permafrost landforms, demonstrate the capability of the InSAR technique to remotely monitor surface deformation of individual DTLBs, and illustrate the combination of ground-based and remote sensing observations to estimate thaw strain. Our study highlights the need for better description of the spatial heterogeneity of landscape-scale processes for regional assessment of surface dynamics on Arctic coastal lowlands.