• Contributors: Dennis Baldocchi
  • Publication Type: JOUR
  • Authors: Yu, Z., J. X. Wang, S. R. Liu, S. L. Piao, P. Ciais, S. W. Running, B. Poulter, J. S. Rentch, and P. S. Sun

  • IAim Winter snow has been suggested to regulate terrestrial carbon (C) cycling
    by modifying microclimate, but the impacts of change in snow cover on the
    annual C budget at a large scale are poorly understood. Our aim is to quantify
    the C balance under changing snow depth.
    Location Non-permafrost region of the northern forest area.
    Methods Here, we used site-based eddy covariance flux data to investigate the
    relationship between depth of snow cover and ecosystem respiration (Reco)
    during winter. We then used the Biome-BGC model to estimate the effect of
    reductions in winter snow cover on the C balance of northern forests in the
    non-permafrost region.
    Results According to site observations, winter net ecosystem C exchange
    (NEE) ranged from 0.028 to 1.53 gCm22
    , accounting for 44 6 123% of
    the annual C budget. Model simulation showed that over the past 30 years,
    snow-driven change in winter C fluxes reduced non-growing season CO2
    emissions, enhancing the annual C sink of northern forests. Over the entire
    study area, simulated winter Reco significantly decreased by 0.33
    year21 in response to decreasing depth of snow cover, which
    accounts for approximately 25% of the simulated annual C sink trend from
    1982 to 2009.
    Main conclusion Soil temperature is primarily controlled by snow cover
    rather than by air temperature as snow serves as an insulator to prevent
    chilling impacts. A shallow snow cover has less insulation potential, causing
    colder soil temperatures and potentially lower respiration rates. Both eddy
    covariance analysis and model-simulated results show that both Reco and NEE
    are significantly and positively correlated with variation in soil temperature
    controlled by variation in snow depth. Overall, our results highlight that a
    decrease in winter snow cover restrains global warming as less C is emitted to
    the atmosphere.

  • Journal: Global Ecology and Biogeography
  • Funding Agency:
  • Volume: 25
  • No:
  • Pages: 586-595
  • Publication Year: 2016
  • DOI: 10.1111/geb.12441
  • ISBN: