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The modeled seasonal cycles of land biosphere and ocean N2O fluxes and atmospheric N2O
  • +20
  • Qing Sun,
  • Fortunat Joos,
  • Sebastian Lienert,
  • Sarah Berthet,
  • Dustin Carroll,
  • Cheng Gong,
  • Akihiko Ito,
  • Atul Jain,
  • Sian Kou-Giesbrecht,
  • Angela Landolfi,
  • Manfredi Manizza,
  • Naiqing Pan,
  • Michael J. Prather,
  • Pierre Regnier,
  • Laure Resplandy,
  • Roland Séférian,
  • Hao Shi,
  • Parvadha Suntharalingam,
  • Rona L. Thompson,
  • Hanqin Tian,
  • Nicolas Vuichard,
  • Sönke Zaehle,
  • Qing Zhu
Qing Sun
Climate and Environmental Physics, Physics Institute, University of Bern

Corresponding Author:[email protected]

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Fortunat Joos
University of Bern
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Sebastian Lienert
University of Bern Physics Institute Climate and Environmental Physics & Oschger Centre for Climate Change Research
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Sarah Berthet
Centre National de Recherches Météorologiques
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Dustin Carroll
Moss Landing Marine Laboratories
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Cheng Gong
Max Planck Institute for Biogeochemistry
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Akihiko Ito
National Institute for Environmental Studies
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Atul Jain
University of Illinois, Urbana-Champaign
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Sian Kou-Giesbrecht
Dalhousie University
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Angela Landolfi
Institute of Marine Sciences, National Research Council (ISMAR-CNR), Via Fosso del Cavaliere 100
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Manfredi Manizza
Scripps Institution of Oceanography
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Naiqing Pan
Auburn University
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Michael J. Prather
University of California, Irvine
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Pierre Regnier
Department Geoscience, Environment & Society - BGEOSYS, Université Libre de Bruxelles,
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Laure Resplandy
Princeton University
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Roland Séférian
CNRM (Météo-France/CNRS)
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Hao Shi
Research Center for Eco-Environmental Sciences
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Parvadha Suntharalingam
University of East Anglia
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Rona L. Thompson
Norwegian Institute for Air Research
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Hanqin Tian
Schiller Institute for Integrated Science and Society, Boston College
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Nicolas Vuichard
LSCE-IPSL
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Sönke Zaehle
Max Planck Institute for Biogeochemistry
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Qing Zhu
Lawrence Berkeley National Laboratory (DOE)
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Abstract

Nitrous oxide (N2O) is a greenhouse gas and an ozone-depleting agent with large and growing anthropogenic emissions. Previous studies identified the influx of N2O-depleted air from the stratosphere to partly cause the seasonality in tropospheric N2O (aN2O), but other contributions remain unclear. Here we combine surface fluxes from eight land and four ocean models from phase 2 of the Nitrogen/N2O Model Intercomparison Project with tropospheric transport modeling to simulate aN2O at the air sampling sites: Alert, Barrow, Ragged Point, Samoa, Ascension Island, and Cape Grim for the modern and preindustrial periods. Models show general agreement on the seasonal phasing of zonal-average N2O fluxes for most sites, but, seasonal peak-to-peak amplitudes differ severalfold across models. After transport, the seasonal amplitude of surface aN2O ranges from 0.25 to 0.80 ppb (interquartile ranges 21-52% of median) for land, 0.14 to 0.25 ppb (19-42%) for ocean, and 0.13 to 0.76 ppb (26-52%) for combined flux contributions. The observed range is 0.53 to 1.08 ppb. The stratospheric contributions to aN2O, inferred by the difference between surface-troposphere model and observations, show 36-126% larger amplitudes and minima delayed by ~1 month compared to Northern Hemisphere site observations. Our results demonstrate an increasing importance of land fluxes for aN2O seasonality, with land fluxes and their seasonal amplitude increasing since the preindustrial era and are projected to grow under anthropogenic activities. In situ aN2O observations and atmospheric transport-chemistry models will provide opportunities for constraining terrestrial and oceanic biosphere models, critical for projecting surface N2O sources under ongoing global warming.
23 Oct 2023Submitted to ESS Open Archive
27 Oct 2023Published in ESS Open Archive