Terrestrial carbon, water and energy fluxes measured by eddy covariance, and associated biomet variables, at a shrub tundra ecosystem near Toolik Lake, Alaska, 2018-2024

This Arctic Observing Network (AON) project focuses on maintaining and expanding our long-term network of measurements of carbon, water, and energy exchange in terrestrial systems in Alaska. These exchanges help regulate the Arctic System and its feedbacks to global climate. Thus, extending long-term observations is a key science priority for the observing-change component of the Study of Environmental Arctic Change (SEARCH). Detecting and interpreting change in arctic carbon (C), water, and energy fluxes requires a continuous year-round record over multiple years. Recent data syntheses and modeling studies of Arctic Carbon balance suggest that tundra is either a carbon dioxide (CO2) sink, a source, or neutral (e.g., McGuire et al., 2009, McGuire et al., 2012) . This uncertainty arises mainly from a lack of data on winter CO2 flux and how tundra responds to recent warming. Because of harsh, remote environments and the lack of line power, long-term measurements of arctic CO2 fluxes over the full year are rare. We have been measuring year-round C, water, and energy fluxes for eleven years in two broadly representative flagship observatories with long-term histories of research, at Imnavait Creek near Toolik Lake, Alaska, and near Cherskiy, Siberia. Similar versions of these eddy covariance and biomet data are available from Ameriflux as sites US-xxx. https://ameriflux.lbl.gov/data/download-data/ Shrub tundra (TK_SHRB) 68.633642, -149.576959