Methane and carbon dioxide gas fluxes measured by eddy covariance at a thermokarst mound site in Interior Alaska (2020-2023)

Greenhouse gas fluxes (methane [CH4] and carbon dioxide [CO2]) measured at a eddy covariance tower with ~200 meter (m) fetch at North Star Yedoma (NSY), a grassland field in interior Alaska characterized by thermokarst (thaw) mounds forming due to degradation of ice-rich Yedoma, polygonal-ground permafrost soil. Measurements were made year-round from May 2020 through May 2023. Air and soil temperature and soil moisture were measured in-situ with buried sensors connected to a datalogger. Thermokarst mounds are regularly spaced conical hills (≤15 meters (m) diameter, ≤5 m height) separated by trenches (≤3 m width) that form in degrading ice-rich Yedoma permafrost environments. Their formation and morphology are based on the melting of large syngenetic ice wedges in polygonal patterned ground, where the polygon margins (trenches) underlain by ice wedges subside faster and deeper than the less ice-rich polygon centers (mound tops), leaving behind distinct conical-mound features in regularly-spaced patterns. Thermokarst mounds are known to emit nitrous oxide [Marushchak et al. 2021, doi.org/10.1038/s41467-021-27386-2], but their carbon fluxes have until now remained largely uncharacterized. This data set provides continuous multiyear characterization of greenhouse gas fluxes at the NSY site in interior Alaska.
Marushchak, M.E., Kerttula, J., Diáková, K. et al. Thawing Yedoma permafrost is a neglected nitrous oxide source. Nat Commun 12, 7107 (2021). https://doi.org/10.1038/s41467-021-27386-2