TY - JOUR
T1 - Large-Scale Droughts Responsible for Dramatic Reductions of Terrestrial Net Carbon Uptake Over North America in 2011 and 2012
AU - He, Wei
AU - Ju, Weimin
AU - Schwalm, Christopher R.
AU - Sippel, Sebastian
AU - Wu, Xiaocui
AU - He, Qiaoning
AU - Song, Lian
AU - Zhang, Chunhua
AU - Li, Jing
AU - Sitch, Stephen
AU - Viovy, Nicolas
AU - Friedlingstein, Pierre
AU - Jain, Atul K.
N1 - Funding Information:
This research is funded by National Key R&D Program of China (2016YFA0600202). C. Zhang is partially funded by the National Natural Science Foundation of China (grant 41601054). We thank Ivar R. van der Velde for providing the SiBCASA simulations. The CRUNCEP v6 data are available at https://vesg.ipsl.upmc.fr/thredds/catalog/store/p529viov/cruncep/V6_1901_2014/catalog.html. The GLEAM soil moisture and ET data are publicly available at http://www.gleam.eu/. The GRACE TWS data provided by NASA JPL, CSR (University of Texas Center for Space Research), and GFZ (the GeoForschungsZentrum Potsdam) are available at http://podaacftp.jpl.nasa.gov/allData/tellus/L3/land_mass/RL05. The GOME-2 SIF V26 data are publicly available at https://acd-ext.gsfc.nasa.gov/People/Joiner/my_gifs/GOME_F/GOME-F.htm. The MODIS EVI data are available at https://lpdaac.usgs.gov. The TRENDY data (http://dgvm.ceh.ac.uk/) are available from Stephen Sitch (S.A.Sitch@exeter.ac.uk) or Pierre Friedlingstein (p.friedlingstein@exeter.ac.uk) through e-mail request. The FLUXCOM data are publicly available at http://www.fluxcom.org. The CarbonTracker Europe 2016 data are publicly available at http://www.carbontracker.eu. The CarbonTracker 2016 data are publicly available at https://www.esrl.noaa.gov/gmd/ccgg/carbontracker/index.php.
Funding Information:
1International Institute for Earth System Science, Nanjing University, Nanjing, China, 2Center for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen, University of Groningen, Groningen, Netherlands, 3Jiangsu Center for Collaborative Innovation in Geographic Information Resource Development and Application, Nanjing, China, 4Woods Hole Research Center, Falmouth, MA, USA, 5Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA, 6Norwegian Institute of Bioeconomy Research, Ås, Norway, 7Department of Microbiology and Plant Biology, Center for Spatial Analysis, University of Oklahoma, Norman, OK, USA, 8School of Urban and Environmental Sciences, Huaiyin Normal University, Huaian, China, 9School of Resources and Environmental Engineering, Ludong University, Yantai, China, 10College of Life and Environmental Sciences, University of Exeter, Exeter, UK, 11Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, Gif-sur-Yvette, France, 12Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
Publisher Copyright:
©2018. American Geophysical Union. All Rights Reserved.
PY - 2018/7
Y1 - 2018/7
N2 - Recently, severe droughts that occurred in North America are likely to have impacted its terrestrial carbon sink. However, process-based understanding of how meteorological conditions prior to the onset of drought, for instance warm or cold springs, affect drought-induced carbon cycle effects remains scarce. Here we assess and compare the response of terrestrial carbon fluxes to summer droughts in 2011 and 2012 characterized by contrasting spring conditions. The analysis is based on a comprehensive ensemble of carbon cycle models, including FLUXCOM, TRENDY v5, SiBCASA, CarbonTracker Europe, and CarbonTracker, and emerging Earth observations. In 2011, large reductions of net ecosystem production (NEP; −0.24 ± 0.17 Pg C/year) are due to decreased gross primary production (−0.17 ± 0.18 Pg C/year) and slightly increased ecosystem respiration (+0.07 ± 0.17 Pg C/year). Conversely, in 2012, NEP reductions (−0.17 ± 0.25 Pg C/year) are attributed to a larger increase of ecosystem respiration (+0.48 ± 0.27 Pg C/year) than gross primary production (+0.31 ± 0.29 Pg C/year), induced predominantly by an extra warmer spring prior to summer drought. Two temperate ecoregions crops/agriculture and the grass/shrubs contribute largest to these reductions and also dominate the interannual variations of NEP during 2007–2014. Moreover, the warming spring compensated largely the negative carbon anomaly due to summer drought, consistent with earlier studies; however, the compensation occurred only in some specific ecoregions. Overall, our analysis offers a refined view on recent carbon cycle variability and extremes in North America. It corroborates earlier results but also highlights differences with respect to ecoregion-specific carbon cycle responses to drought and heat.
AB - Recently, severe droughts that occurred in North America are likely to have impacted its terrestrial carbon sink. However, process-based understanding of how meteorological conditions prior to the onset of drought, for instance warm or cold springs, affect drought-induced carbon cycle effects remains scarce. Here we assess and compare the response of terrestrial carbon fluxes to summer droughts in 2011 and 2012 characterized by contrasting spring conditions. The analysis is based on a comprehensive ensemble of carbon cycle models, including FLUXCOM, TRENDY v5, SiBCASA, CarbonTracker Europe, and CarbonTracker, and emerging Earth observations. In 2011, large reductions of net ecosystem production (NEP; −0.24 ± 0.17 Pg C/year) are due to decreased gross primary production (−0.17 ± 0.18 Pg C/year) and slightly increased ecosystem respiration (+0.07 ± 0.17 Pg C/year). Conversely, in 2012, NEP reductions (−0.17 ± 0.25 Pg C/year) are attributed to a larger increase of ecosystem respiration (+0.48 ± 0.27 Pg C/year) than gross primary production (+0.31 ± 0.29 Pg C/year), induced predominantly by an extra warmer spring prior to summer drought. Two temperate ecoregions crops/agriculture and the grass/shrubs contribute largest to these reductions and also dominate the interannual variations of NEP during 2007–2014. Moreover, the warming spring compensated largely the negative carbon anomaly due to summer drought, consistent with earlier studies; however, the compensation occurred only in some specific ecoregions. Overall, our analysis offers a refined view on recent carbon cycle variability and extremes in North America. It corroborates earlier results but also highlights differences with respect to ecoregion-specific carbon cycle responses to drought and heat.
KW - Earth observation
KW - North America
KW - carbon cycle model
KW - carbon uptake
KW - drought
KW - spring warming
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U2 - 10.1029/2018JG004520
DO - 10.1029/2018JG004520
M3 - Article
AN - SCOPUS:85050877592
SN - 2169-8953
VL - 123
SP - 2053
EP - 2071
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 7
ER -