Direct current (DC) resistivity and induced polarization (IP) monitoring of active layer dynamics at high temporal resol

J. Doetsch, G. Fiandaca, T. Ingeman-Nielsen, G. Fiandaca, A. V. Christiansen, E. Auken, B. Elberling

Publikation: Bidrag til bog/rapport/konferenceproceedingsKonferenceartikel i proceedingspeer review

2 Citationer (Scopus)

Abstrakt

With permafrost thawing and changes in active layer dynamics induced by climate change, interactions between biogeochemical and thermal processes in the ground are of great importance. Here, active layer dynamics have been monitored using direct current (DC) resistivity and induced polarization (IP) measurements at high temporal resolution at a heath tundra site on Disko Island on the west coast of Greenland (69°N). Borehole sediment characteristics and subsurface temperatures supplemented the DCIP measurements. Data acquired during the freezing period of October 2013 - February 2014 clearly image the soil freezing as a strong increase in resistivity. While the freezing horizon generally moves deeper with time, some variations in the freezing depth are observed along the profile. Comparison with depth-specific soil temperature indicates an exponential relationship between resistivity and belowfreezing temperature. Time-lapse inversions of the full-decay IP data indicate a decrease of normalized chargeability with freezing of the ground, which can be the result of a decrease in the total unfrozen water and thus a higher ion concentration in the pore-water. We conclude that DC-IP time-lapse measurements can non-intrusively and reliably image freezing patterns and their lateral variation on a 10-100 m scale that is difficult to sample by point measurements.

OriginalsprogEngelsk
TitelNear Surface Geoscience 2015 - 21st European Meeting of Environmental and Engineering Geophysics
ForlagEuropean Association of Geoscientists and Engineers, EAGE
Sider291-295
Antal sider5
ISBN (Elektronisk)9781510814127
DOI
StatusUdgivet - 2015
Begivenhed21st European Meeting of Environmental and Engineering Geophysics, Near Surface Geoscience 2015 - Turin, Italien
Varighed: 6 sep. 201510 sep. 2015

Publikationsserier

NavnNear Surface Geoscience 2015 - 21st European Meeting of Environmental and Engineering Geophysics

Konference

Konference21st European Meeting of Environmental and Engineering Geophysics, Near Surface Geoscience 2015
Land/OmrådeItalien
ByTurin
Periode6/09/1510/09/15

Programområde

  • Programområde 2: Vandressourcer

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