Munger, J. (Bill): Harvard University (Project Lead)
Commane, Róisín: Columbia University (Co-Investigator)
Henderson, John: AER (Co-Investigator)
Moorcroft, Paul: Harvard University (Co-Investigator)
Oechel, Walter (Walt): San Diego State University (Co-Investigator)
Wofsy, Steven (Steve): Harvard University (Co-Investigator)
Zona, Donatella: San Diego State University (Co-Investigator)
Biraud, Sebastien: Lawrence Berkeley National Laboratory (Collaborator)
Luus, Kristina: MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DERWISSENSCHAFTEN E.V. (Collaborator)
Sweeney, Colm: NOAA GML (Collaborator)
Euskirchen, Eugenie: University of Alaska, Fairbanks (Participant)
Larson, Erik: Harvard (Post-Doc)
Schiferl, Luke: Lamont-Doherty Earth Observatory (Post-Doc)
Project Funding:
2017 - 2020
NRA: 2016 NASA: Carbon Cycle Science
Funded by NASA
Abstract:
Background and Objectives
Transition seasons in Arctic tundra are particularly important for the ecosystem's short- and long-term carbon balance and for the long-term carbon balance. Climate-driven changes in the timing of seasonal transitions can affect whether the annual carbon balance for an ecosystem is positive or negative, but detailed understanding of processes that control arctic carbon cycling during this period lags behind understanding of growing season processes. Year-round eddy flux tower and seasonal aircraft observations of CO2 and CH4 fluxes at far northern tundra sites demonstrate previously unrecognized carbon exchange during transition seasons. Notably, the spring onset of carbon uptake is not accurately predicted using vegetation greenness defined by traditional satellite vegetation indices, and elevated carbon emissions extend well into the cold season when air and surface soil temperatures have fallen below freezing. We propose an in-depth analysis that integrates surface and airborne in situ data for CO2 and CH4 concentrations, remote sensing of vegetation and soils, satellite observations of Solar Induced Fluorescence (SIF) and CO2 and CH4 columns, tower fluxes, and meteorological products into a model-data synthesis framework that will improve our understanding of how the large pool of carbon stored in frozen tundra soils is responding to changing climate conditions. We will examine whether observed changes in transition season carbon exchange at local scalesare occurring throughout the entire region and identify the environmental state variables that can best predict the timing of seasonal transitions across the tundra.
Methodology
We will test empirical functional models and process-based terrestrial ecosystem models against observations by comparing measured atmospheric CO2 and CH4 concentrations to concentrations predicted from applying atmospheric mixing and transport models to predictions of carbon uptake and emission. Using atmospheric data rather than flux measurements at a particular site tests whether the models accurately represent the regional mix of different environmental conditions and vegetation characteristics.
Significance
The proposed work responds to the call for carbon research in the critical arctic ecosystem. Specifically, we will use an array of observational data to challenge and improve ecosystem models at scales from individual landscape patch up to regional scales. By quantitatively assessing model simulations against observations at regional scales we will identify gaps in our understanding of carbon dynamics and climate feedbacks, and contribute to an improved quantitative and predictive understanding of processes that regulate carbon cycling from northern terrestrial ecosystems.
Publications:
Larson, E. J. L., Schiferl, L. D., Commane, R., Munger, J. W., Trugman, A. T., Ise, T., Euskirchen, E. S., Wofsy, S., Moorcroft, P. M. 2021. The changing carbon balance of tundra ecosystems: results from a vertically-resolved peatland biosphere model. Environmental Research Letters. 17(1), 014019. DOI: 10.1088/1748-9326/ac4070
Schiferl, L. D., Watts, J. D., Larson, E. J. L., Arndt, K. A., Biraud, S. C., Euskirchen, E. S., Henderson, J. M., McKain, K., Mountain, M. E., Munger, J. W., Oechel, W. C., Sweeney, C., Yi, Y., Zona, D., Commane, R. Using atmospheric observations to quantify annual biogenic carbon dioxide fluxes on the Alaska North Slope DOI: 10.5194/bg-2022-167
More details may be found in the following project profile(s):
