Estimating active layer thickness and volumetric water content from ground penetrating radar measurements in Barrow, Alaska.

E E Jafarov,K Schaefer,L Liu,A D Parsekian,S K Panda,T Zhang,A C Chen

doi:10.1002/gdj3.49

Abstract

Ground penetrating radar (GPR) has emerged as an effective tool for estimating active layer thickness (ALT) and volumetric water content (VWC) within the active layer. In August 2013, we conducted a series of GPR and probing surveys using a 500 MHz antenna and metallic probe around Barrow, Alaska. We collected about 15 km of GPR data and 1.5 km of probing data. Here, we describe the GPR data processing workflow from raw GPR data to the estimated ALT and VWC. We include the corresponding uncertainties for each measured and estimated parameter. The estimated average GPR‐derived ALT was 41 cm, with a standard deviation of 9 cm. The average probed ALT was 40 cm, with a standard deviation of 12 cm. The average GPR‐derived VWC was 0.65, with a standard deviation of 0.14.

Highlights

Active layer thickness (ALT) is the maximum depth of thaw of the surface soils in permafrost-affected soils
Geoscience Data Journal published by Royal Meteorological Society and John Wiley & Sons Ltd
To complement the direct comparison of the probed versus Ground penetrating radar (GPR) ALTs, plot the distribution of the difference between probed and GPR data and the number of points used in the difference calculation

Summary

Introduction

Active layer thickness (ALT) is the maximum depth of thaw of the surface soils in permafrost-affected soils. ALT is identified as one of the essential variables for monitoring the status of permafrost (Brown et al, 2008). Ground penetrating radar (GPR) is a non-invasive geophysical technology that allows nearly continuous spatial estimates of ALT and enables better understanding of permafrost distribution and thermal dynamics. GPR uses pulses of radio-frequency (~25 MHz to 2.5 GHz) electromagnetic waves emitted at the ground surface to investigate the subsurface. The energy from these pulses reflects at boundaries between materials of contrasting dielectric permittivity (Neal, 2004; Jol, 2009). Thawed soil in the active layer has higher a 2017 The Authors.

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Conclusion