Continuous measurements of atmospheric methane (CH4) mole fractions measured by NOAA's Global Greenhouse Gas Reference Network in Barrow, AK (BRW), show strong enhancements above background values when winds come from the land sector from July to December from 1986 to 2015, indicating that emissions from arctic tundra continue through autumn and into early winter.

Original Source

Studies diverge substantially on the actual magnitude of the North American carbon budget. This is due to the lack of appropriate data and also stems from the difficulty to properly model all the details of the flux distribution and transport inside the region of interest.