English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. Characterizing methane sources in the Arctic remains challenging due to the remoteness, heterogeneity and variety of such emissions. Insitu campaigns provide valuable datasets to reduce these uncertainties. Here we analyse data from the summer 2014 SWERUS-C3 campaign in theeastern Arctic Ocean, off the shore of Siberia and Alaska. Total concentrations of methane, as well as relative concentrations of 12CH4 and13CH4, were measured continuously during this campaign for 35 d in July and August. Using a chemistry-transport model, we linkobserved concentrations and isotopic ratios to regional emissions and hemispheric transport structures. A simple inversion system helped constrainsource signatures from wetlands in Siberia and Alaska, and oceanic sources, as well as the isotopic composition of lower-stratosphere air masses.The variation in the signature of lower-stratosphere air masses, due to strongly fractionating chemical reactions in the stratosphere, was suggestedto explain a large share of the observed variability in isotopic ratios. These results point towards necessary efforts to better simulate large-scaletransport and chemistry patterns to make relevant use of isotopic data in remote areas. It is also found that constant and homogeneous sourcesignatures for each type of emission in a given region (mostly wetlands and oil and gas industry in our case at high latitudes) are not compatiblewith the strong synoptic isotopic signal observed in the Arctic. A regional gradient in source signatures is highlighted between Siberian andAlaskan wetlands, the latter having lighter signatures (more depleted in 13C). Finally, our results suggest that marine emissions ofmethane from Arctic continental-shelf sources are dominated by thermogenic-origin methane, with a secondary biogenic source as well.

Using ship-borne observations of methane isotopic ratio in the Arctic Ocean to understand methane sources in the Arctic