title: Detecting regional patterns of changing CO2 flux in Alaska.
abstract: With rapid changes in climate and the seasonal amplitude of carbon dioxide (CO2) in the Arctic, it is critical that we detect and quantify the underlying processes controlling the changing amplitude of CO2 to better predict carbon cycle feedbacks in the Arctic climate system. We use satellite and airborne observations of atmospheric CO2 with climatically forced CO2 flux simulations to assess the detectability of Alaskan carbon cycle signals as future warming evolves. We find that current satellite remote sensing technologies can detect changing uptake accurately during the growing season but lack sufficient cold season coverage and near-surface sensitivity to constrain annual carbon balance changes at regional scale. Airborne strategies that target regular vertical profile measurements within continental interiors are more sensitive to regional flux deeper into the cold season but currently lack sufficient spatial coverage throughout the entire cold season. Thus, the current CO2 observing network is unlikely to detect potentially large CO2 sources associated with deep permafrost thaw and cold season respiration expected over the next 50 y. Although continuity of current observations is vital, strategies and technologies focused on cold season measurements (active remote sensing, aircraft, and tall towers) and systematic sampling of vertical profiles across continental interiors over the full annual cycle are required to detect the onset of carbon release from thawing permafrost.
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109; Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, CA 90095; nicholas.c.parazoo@jpl.nasa.gov.
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Parazoo
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138; Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
authors.forename: Roisin
authors.identifier: 0000-0003-1373-1550
authors.initials: R
authors.lastname: Commane
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138; Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138;
authors.forename: Steven C
authors.initials: SC
authors.lastname: Wofsy
authors.affiliation: Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
authors.forename: Charles D
authors.initials: CD
authors.lastname: Koven
authors.affiliation: National Oceanic and Atmospheric Administration/Earth System Research Laboratory, Boulder, CO 80305; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309;
authors.forename: Colm
authors.initials: C
authors.lastname: Sweeney
authors.affiliation: Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80302;
authors.forename: David M
authors.initials: DM
authors.lastname: Lawrence
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138; Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523;
authors.forename: Jakob
authors.initials: J
authors.lastname: Lindaas
authors.affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada B3H 4R2.
authors.forename: Rachel Y-W
authors.initials: RY
authors.lastname: Chang
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109;
authors.forename: Charles E
authors.initials: CE
authors.lastname: Miller
keywords: Earth system models; carbon cycle; climate; permafrost thaw; remote sensing