Publication Date
7-1-2024
Document Type
Article
Publication Title
Global Biogeochemical Cycles
Volume
38
Issue
7
DOI
10.1029/2023GB008010
Abstract
Nitrous oxide (N2O) is a greenhouse gas and stratospheric ozone-depleting substance 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 eight remote air sampling sites for modern and pre-industrial periods. Models show general agreement on the seasonal phasing of zonal-average N2O fluxes for most sites, but seasonal peak-to-peak amplitudes differ several-fold across models. The modeled seasonal amplitude of surface aN2O ranges from 0.25 to 0.80 ppb (interquartile ranges 21%–52% of median) for land, 0.14–0.25 ppb (17%–68%) for ocean, and 0.28–0.77 ppb (23%–52%) for combined flux contributions. The observed seasonal amplitude ranges from 0.34 to 1.08 ppb for these sites. The stratospheric contributions to aN2O, inferred by the difference between the surface-troposphere model and observations, show 16%–126% larger amplitudes and minima delayed by ∼1 month compared to Northern Hemisphere site observations. Land fluxes and their seasonal amplitude have increased since the pre-industrial era and are projected to grow further under anthropogenic activities. Our results demonstrate the increasing importance of land fluxes for aN2O seasonality. Considering the large model spread, in situ aN2O observations and atmospheric transport-chemistry models will provide opportunities for constraining terrestrial and oceanic biosphere models, critical for projecting carbon-nitrogen cycles under ongoing global warming.
Funding Number
200020 200511
Funding Sponsor
Ministry of the Environment, Government of Japan
Keywords
ocean biogeochemistry model, seasonal cycle, surface N O emissions 2, terrestrial biosphere model, tropospheric N O 2
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License
Department
Moss Landing Marine Laboratories
Recommended Citation
Qing Sun, Fortunat Joos, Sebastian Lienert, Sarah Berthet, Dustin Carroll, Cheng Gong, Akihiko Ito, Atul K. Jain, Sian Kou-Giesbrecht, Angela Landolfi, Manfredi Manizza, Naiqing Pan, Michael Prather, Pierre Regnier, Laure Resplandy, Roland Séférian, Hao Shi, Parvadha Suntharalingam, and Rona L. Thompson. "The Modeled Seasonal Cycles of Surface N2O Fluxes and Atmospheric N2O" Global Biogeochemical Cycles (2024). https://doi.org/10.1029/2023GB008010
