Estimations of moisture content in the active layer in an Arctic ecosystem by using ground-penetrating radar profiling

We applied high-frequency GPR at a study site in the high arctic ecosystem of Northeast Greenland to evaluate its usefulness in assessing depth of, and water content in, the active layer at Zackenberg Valley (74°N; 20°W) to evaluate its usefulness in the high arctic ecosystems. The study site includes different vegetation types, and it well represents of the entire valley, for which we aimed to determine the conditions and characteristics that influence the GPR performance in the active layer. The spatial distribution of moisture content along the transect studied was estimated using GPR data (400MHz antenna), depth to permafrost, soil samples and vegetation observations. Vertical distribution of the water content in the unfrozen soil bulk was predicted for several points on the transect by combining data that influence the behavior of the radar waves with that of capacitive moisture probes. The statistical models resulted to be highly significant, thus assuming common conditions of the soil to the classified vegetation, we can obtain from the GPR data, truthful estimations of water content, and, moreover, we can predict the distribution to the bottom of the active layer. Hence, we conclude that GPR is a viable option for improving active layer spatial quantification of water contents that can be used to assess changes in the active layer in arctic regions. ► Hydrological conditions influence the vegetation and therefore the entire Arctic ecosystem. ► Moisture content was estimated from field observations and geophysical methods. ► Dielectric permittivity was obtained from GPR to relate it to water content. ► The relationship between moisture and vegetation distribution showed to be consistent. ► The attenuated signal was used to estimate the vertical distribution of water content.