A thermokarst lake is a body of water that occupies a depression created by subsidence following the decay of ground ice and permafrost. Perennially unfrozen bodies within the permafrost, called taliks, occur under these thermokarst lakes. The geometry of these taliks and the processes that created them are important for understanding interations between surface water, groundwater, and atmospheric carbon and methane flux as these lakes cover a significant portion of the arctic coastal regions around the world.
Due to the possible depths of these taliks, which can extend for tens of meters, direct measurements of talik geometry is difficult. Surface nuclear magnetic resonance (NMR) is a promising non-invasive geophysical tool that provides a direct measurement of water content. My research focuses on using NMR and other geophysical techniques to understand talik geometry and permafrost thaw and its effect on hydrology and to inform climate models.
The first step of this reseach was conducted in October 2014 with a trip to a thermokarst lake outside of Fairbanks, Alaska.
Measuring ice thickness on the lake
laying out NMR loops
collecting data
photos courtsey of Andrew Parsekian