This dataset includes two data tables of methane (CH4) fluxes measured in Arctic uplands. Dataset 1 contains CH4 fluxes measured at high temporal resolution (hourly fluxes) collected over two snow-free seasons (June–August; 2019, 2021) at Trail Valley Creek, an Arctic tundra site in the Western Canadian Arctic. Fluxes were measured with automated chambers installed in replication of six at three individual landcover vegetation units (Lichen, Shrub, Tussock) within dwarf-shrub dominated tundra. Site meteorological data are provided with the flux data at hourly resolution. Dataset 2 includes campaign-based, manual chamber measurements at sites displaying net CH4 uptake. These manual measurements were conducted during the growing season at typical, well-drained upland sites, which included, besides Trail Valley Creek, three additional sites in the Canadian and European Arctic (Havikpak Creek, Scotty Creek, Kilpisjärvi). Besides CH4 flux observations, dataset 2 contains measured greenhouse gas concentration profiles of CH4, carbon dioxide (CO2) and nitrous oxide (N2O) at 2 cm, 5 cm, 10 cm, and 20 cm soil depths, as well as site meteorological data. While wetlands are known CH4 emitters, drier arctic and boreal uplands may act as sinks of atmospheric CH4. The scope of the study and this dataset is to improve the spatial and temporal coverage of low CH4 emitting and sites displaying net CH4 uptake across the Arctic. Both datasets are meant as supplement to the published study, where further, detailed information on site conditions and methodology can be found.

Further funding awards: NSERC Discovery Grants program (DGPIN-2018-05743 and RGPIN-2022-05347), Atmosphere and Climate Competence Center (ACCC, no. 337550), Northern Water Futures (Global Water Futures, Canada First Research Excellence Fund's Global Water Futures program, doi:10.13039/501100013380), Polar Continental Shelf Program (608-20, 602-21)