title: Drought rapidly diminishes the large net CO2uptake in 2011 over semi-arid Australia.
abstract: Each year, terrestrial ecosystems absorb more than a quarter of the anthropogenic carbon emissions, termed as land carbon sink. An exceptionally large land carbon sink anomaly was recorded in 2011, of which more than half was attributed to Australia. However, the persistence and spatially attribution of this carbon sink remain largely unknown. Here we conducted an observation-based study to characterize the Australian land carbon sink through the novel coupling of satellite retrievals of atmospheric CO2and photosynthesis and in-situ flux tower measures. We show the 2010-11 carbon sink was primarily ascribed to savannas and grasslands. When all biomes were normalized by rainfall, shrublands however, were most efficient in absorbing carbon. We found the 2010-11 net CO2uptake was highly transient with rapid dissipation through drought. The size of the 2010-11 carbon sink over Australia (0.97 Pg) was reduced to 0.48 Pg in 2011-12, and was nearly eliminated in 2012-13 (0.08 Pg). We further report evidence of an earlier 2000-01 large net CO2uptake, demonstrating a repetitive nature of this land carbon sink. Given a significant increasing trend in extreme wet year precipitation over Australia, we suggest that carbon sink episodes will exert greater future impacts on global carbon cycle.
authors.affiliation: Climate Change Cluster, University of Technology Sydney, Broadway, New South Wales, 2007, Australia.
authors.forename: Xuanlong
authors.initials: X
authors.lastname: Ma
authors.affiliation: Climate Change Cluster, University of Technology Sydney, Broadway, New South Wales, 2007, Australia.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Huete
authors.affiliation: School of Life Sciences, University of Technology Sydney, Broadway, New South Wales, 2007, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Cleverly
authors.affiliation: School of Life Sciences, University of Technology Sydney, Broadway, New South Wales, 2007, Australia.
authors.forename: Derek
authors.initials: D
authors.lastname: Eamus
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, CEA/CNRS/UVSQ, Gif-sur-Yvette, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Chevallier
authors.affiliation: NASA Goddard Space Flight Centre, Laboratory for Atmospheric Chemistry and Dynamics, Greenbelt, Maryland, 20771, United States.
authors.forename: Joanna
authors.initials: J
authors.lastname: Joiner
authors.affiliation: Institute on Ecosystems and Department of Ecology, Montana State University, Bozeman, Montana, 59717, United States.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Poulter
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, International Institute for Earth System Sciences, Nanjing University, Nanjing, Jiangsu, 210023, China.|Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, Jiangsu, 210023, China.
authors.forename: Yongguang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany.
authors.forename: Luis
authors.initials: L
authors.lastname: Guanter
authors.affiliation: Environment Institute, Ecology and Environment Science, University of Adelaide, South Australia, 5005, Australia.
authors.forename: Wayne
authors.initials: W
authors.lastname: Meyer
authors.affiliation: Climate Change Cluster, University of Technology Sydney, Broadway, New South Wales, 2007, Australia.
authors.forename: Zunyi
authors.initials: Z
authors.lastname: Xie
authors.affiliation: USDA Agricultural Research Service, Southwest Watershed Research Centre, Tucson, Arizona, 85719, United States.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Ponce-Campos