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Alaska permafrost characterization: Geophysical and related field data collected from 2016-2017

November 16, 2018

Electrical resistivity tomography (ERT), downhole nuclear magnetic resonance (NMR), and manual permafrost-probe measurements were used to quantify permafrost characteristics along transects within several catchments in interior Alaska in late summer 2016 and 2017. Geophysical sites were chosen to coincide with additional soil, hydrologic, and geochemical measurements adjacent to various low-order streams and tributaries in a mix of burned and unburned watersheds in both silty and rocky environments. Data were collected in support of the Striegl-01 NASA ABoVE project, "Vulnerability of inland waters and the aquatic carbon cycle to changing permafrost and climate across boreal northwestern North America." Additional geophysical measurements were conducted at the Bonanza Creek LTER and at a thermokarst bog site. ERT transects were 100 - 200 m in length, and produce models of electrical resistivity structure to depths of 10 - 15 m that indicate the distribution of frozen ground with high spatial resolution. Manual permafrost-probe measurements were made periodically along ERT transects to validate the depth to the top of permafrost. Downhole NMR measurements were made at select locations near the ERT transects to quantify in situ unfrozen water content and to help constrain interpretations of electrical resistivity models.