Patterns of Spatial Methane Distribution in the Upper Layers of the Permafrost in Central Yakutia

Brief Communication: The reliability of gas extraction techniques for analysing CH<sub>4</sub> and N<sub>2</sub>O compositions in gas trapped in permafrost ice-wedges

“…However, given that the above evidence resulted from three consecutive cycles of melting-refreezing and evacuation, it is unclear how many melting-refreezing cycles are required to extract most of the N2O from ice wedges. Our findings imply that previous estimates of CH4 budget in ground ice based on wet extraction principle (e.g., Boereboom et al, 2013;Cherbunina et al, 2018) https://doi.org/10.5194/tc-2019-231 Preprint. Discussion started: 21 October 2019 c Author(s) 2019.…”

“…4) Our results indicate that previous estimates of ground ice CH4 and N2O budget might be underestimated, implying that the greenhouse gas production in subfreezing environment of permafrost is larger than our current understanding. 5) Our finding indicates that the saturated NaCl solution is unnecessary to prevent microbial activity during melting, as employed by, e.g., Cherbunina et al (2018).…”

“…We noted that the heterogeneous distribution of gas mixing ratios may not have been completely smoothed out by our sub-sample selection, although we randomly chose 8-12 ice cubes for each measurement. Some previous studies have avoided using the wet extraction method because of potential reactivation of microbial CH4 and/or N2O production in ice melt (e.g., Cherbunina et al, 2018;Kim et al, 2019).…”

Methane in Gas Shows from Boreholes in Epigenetic Permafrost of Siberian Arctic

“…Previous studies showed that epigenetic permafrost always contains methane in an average concentration of 2.7 mg CH 4 m −3 (up to 47.4 g CH 4 m −3 ) of frozen sediment as opposed to syngenetic permafrost, which in most cases did not have any detectable methane [17,18]. High concentrations of methane in permafrost deposits were found in redeposited and refrozen sediments of drained thaw lake basins in Central Yakutia [19], whereas moderate concentrations were detected in loams and the segregation ice of marine deposits on the Yamal Peninsula [20]. Methane in permafrost could be produced at temperatures below zero by methanogenic archaea [21], and it could be converted to interpore gas hydrate [22].…”

Dynamic Mapping of Subarctic Surface Water by Fusion of Microwave and Optical Satellite Data Using Conditional Adversarial Networks

“…Spatiotemporally heterogeneous features of surface water created by thermokarst lakes and river networks, which reflect the thawing/freezing of snow (or permafrost) and the related hydrometeorological regime at sub-seasonal to interannual scales, requires observation at a high spatiotemporal resolution to understand the regional water dynamics. Detailed surface water maps are important ancillary data for land-surface modeling [9], soil moisture retrievals [10], and the understanding of methane emissions [11]. Various past studies have provided surface water maps at global scales [12][13][14][15][16]; however, either spatial or temporal details tend to be lost in such existing maps.…”