The Cryosphere Discuss., 7, 5793-5822, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper is under review for the journal The Cryosphere (TC).
Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska
L. Liu1, K. Schaefer2, A. Gusmeroli3, G. Grosse4, B. M. Jones5, T. Zhang2,6, A. D. Parsekian1,*, and H. A. Zebker1
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
*currently at: Department of Geology and Geophysics, University of Wyoming, Laramie Wyoming, USA

Abstract. Drained thermokarst lake basins (DTLBs) are ubiquitous landforms on arctic tundra lowlands, but their present-day dynamic states are seldom investigated. Here we report results based on high-resolution Interferometric Synthetic Aperture Radar (InSAR) measurements using space-borne data for a study area located near Prudhoe Bay, Alaska 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 analyzed exhibited seasonal thaw settlement of 3–4 cm. However, four of the DTLBs analyzed 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.

Citation: Liu, L., Schaefer, K., Gusmeroli, A., Grosse, G., Jones, B. M., Zhang, T., Parsekian, A. D., and Zebker, H. A.: Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska, The Cryosphere Discuss., 7, 5793-5822, doi:10.5194/tcd-7-5793-2013, 2013.
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