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Nitrous Oxide Emissions Estimated With the CarbonTracker‐Lagrange North American Regional Inversion Framework
Author(s) -
Nevison Cynthia,
Andrews Arlyn,
Thoning Kirk,
Dlugokencky Ed,
Sweeney Colm,
Miller Scot,
Saikawa Eri,
Benmergui Joshua,
Fischer Marc,
Mountain Marikate,
Nehrkorn Thomas
Publication year - 2018
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2017gb005759
Subject(s) - nitrous oxide , fertilizer , inversion (geology) , environmental science , greenhouse gas , precipitation , nitrogen , atmospheric sciences , yield (engineering) , agronomy , climatology , meteorology , geography , geology , chemistry , oceanography , paleontology , materials science , organic chemistry , structural basin , metallurgy , biology
Abstract North American nitrous oxide (N 2 O) emissions of 1.6 ± 0.3 Tg N/yr over 2008–2014 are estimated using the CarbonTracker‐Lagrange regional inversion framework. The estimated N 2 O emissions are largely consistent with the EDGAR (Emission Database for Global Atmospheric Research) global inventory and with the results of global atmospheric inversions but offer more spatial and temporal detail over North America. Emissions are strongest from the Midwestern Corn/Soybean Belt, which accounts for nearly one third of the total North American N 2 O source. The emissions are maximum in spring/early summer, consistent with a nitrogen fertilizer‐driven source, and also show a late winter spike suggestive of freeze‐thaw effects. Interannual variability in emissions across the primary months of fertilizer application is positively correlated to mean precipitation. The estimated N 2 O flux from the Midwestern Corn/Soybean Belt and the more northerly United States/Canadian wheat belt corresponds to 4.2–4.6% and 2.2–3.0%, respectively, of total synthetic + organic N fertilizer applied to those regions. Consideration of nonagricultural sources and additional N inputs from soybean N 2 fixation could reduce the N 2 O yield from the Midwestern Corn/Soybean Belt to ~2.2–2.4% of total N inputs.