Methane emission bursts from permafrost environments during autumn freeze-in: New insights from ground-penetrating radar

Research output: Contribution to journalArticle

Abstract

Large amounts of methane (CH4) are known to be emitted from permafrost environments during the autumn freeze-in, but the specific soil conditions leading up to these bursts are unclear. Therefore, we used an ultrawide band ground-penetrating radar in Northeast Greenland in autumn 2009 to estimate the volumetric composition inside the soil through dielectric characterization from 200 to 3200 MHz. Our results suggest a compression of the gas reservoir during the phase transition of soil water, which is accompanied by a peak in surface CH4 emissions. About 1 week thereafter, there seems to be a decompression event, consistent with ground cracking which allows the gas reservoir to expand again. This coincides with the largest CH4 emission, exceeding the summer maximum by a factor of 4. We argue that these complementary measurement techniques are needed to come to an understanding of tundra CH4 bursts connected to soil freezing.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Geosciences, Multidisciplinary
  • Electrical Engineering, Electronic Engineering, Information Engineering

Keywords

  • ground-penetrating radar, Greenland, autumn freeze-in, methane, frequency domain
Original languageEnglish
Pages (from-to)6732-6738
JournalGeophysical Research Letters
Volume42
Issue number16
Publication statusPublished - 2015
Publication categoryResearch
Peer-reviewedYes