Remote Sensing Soil Freeze‐Thaw Status and North American N<sub>2</sub>O Emissions From a Regional Inversion

Nevison, C. D.; X, Lan; Ogle, Stephen M.

doi:10.1029/2023gb007759

Cited by 4 publications

(1 citation statement)

References 37 publications

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“…An analysis using recently published research recommended a revised factor of 1.55 for Western and Eastern ecozones in Canada and estimated NGS emissions to be 35.5% of annual emissions (Pelster et al, 2023). A top-down modeling approach indicated that spring thaw N 2 O emissions could be comparable in size to the growing season maxima induced by N fertilizer application in Canadian cropland (Nevison et al, 2023). Clearly, consideration of freeze-thaw emissions from croplands is important for improved national inventory emission estimates in cold climates.…”

Section: Introductionmentioning

confidence: 99%

Overwinter and Spring Thaw Nitrous Oxide Fluxes in a Northern Prairie Cropland Are Limited but a Significant Proportion of Annual Emissions

Wagner‐Riddle,

Congreves,

Brown

et al. 2024

Global Biogeochemical Cycles

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Croplands that experience seasonal soil freezing and thawing have been shown to be significant sources of N2O emissions. Yet, there is a paucity of year‐round N2O emission data for one of the most significant crop production regions that seasonally freeze, the Prairies. Here, we present micrometeorological N2O fluxes measured over 4 years in Saskatchewan, Canada, to evaluate the magnitude of freeze‐thaw N2O emissions and investigate its driving factors. Significant thaw related emissions occurred in 2 of the 4 years and were associated with relatively higher fall nitrate levels and a more gradual soil thawing period. Overall, fall soil nitrate levels were a strong explanatory variable for the differences in non‐growing season (NGS) N2O emission (r2 = 0.485). Measured cumulative N2O emissions for the NGS were 123–938 g N ha−1 and were much smaller than those obtained at other cold climate sites but amounted to 52% of annual totals on average. The November to April period contributed 30% of the annual total emissions in years without major thaw events, but 70% in years with significant thaws. NGS N2O emissions were not explained by cumulative freezing degree days unlike most other cold climate sites. We propose that NGS N2O emissions are more strongly influenced by thaw dynamics during freezing‐thawing conditions in dry regions, whereas freezing intensity is the dominant factor for wetter regions. Our results indicate that even for a semi‐arid region freeze‐thaw is an important source of N2O emissions and must be considered for more accurate reporting and development of mitigation strategies.

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Section: Introductionmentioning

confidence: 99%

Overwinter and Spring Thaw Nitrous Oxide Fluxes in a Northern Prairie Cropland Are Limited but a Significant Proportion of Annual Emissions

Wagner‐Riddle,

Congreves,

Brown

et al. 2024

Global Biogeochemical Cycles

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Top-down constraints on N2O emissions from Canada

Nevison,

Lan,

Worthy

et al. 2023

Atmospheric Environment

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Airborne Measurements Reveal High Spatiotemporal Variation and the Heavy‐Tail Characteristic of Nitrous Oxide Emissions in Iowa

Dacic,

Plant,

Kort

2024

JGR Atmospheres

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Nitrous oxide (N2O) emissions from croplands contribute substantially to the climate impact of agriculture. Emissions of N2O are controlled by both anthropogenic and environmental factors and can vary by orders of magnitude over short times and distances. This nature of emissions is difficult to capture with models and presents an observational challenge. In the 2021 and 2022 growing season, we collected airborne measurements of N2O over Iowa to characterize N2O emissions at the farm to multi‐county spatial scales across days. We link our airborne observations to surface emissions using a Lagrangian particle dispersion model and quantify emissions using a Bayesian inversion framework. We find emissions magnitudes across Iowa, showing greater skew than modeled predictions, with a small fraction of fields contributing disproportionately to the total [25% of the domain contributing to 52%–77% of total emissions]. In addition to the high spatial variation, we find high temporal variability between flight days by a factor of 2 at the 100 km scale, and an order of magnitude at the 2 km scale], with peak emissions occurring at median soil moisture. This work illustrates the importance of transient, intense emissions from concentrated areas in explaining total cropland emissions, and demonstrates how airborne measurements can provide insights into variation that may be missed by other observational systems. Investigation into environmental factors highlights the need for observations, models and their input data to be spatiotemporally resolved to enable direct comparison, facilitating evaluation of predicted and reported emissions and providing guidance and feedback on mitigation strategies.

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Remote Sensing Soil Freeze‐Thaw Status and North American N₂O Emissions From a Regional Inversion

Cited by 4 publications

References 37 publications

Overwinter and Spring Thaw Nitrous Oxide Fluxes in a Northern Prairie Cropland Are Limited but a Significant Proportion of Annual Emissions

Overwinter and Spring Thaw Nitrous Oxide Fluxes in a Northern Prairie Cropland Are Limited but a Significant Proportion of Annual Emissions

Top-down constraints on N2O emissions from Canada

Airborne Measurements Reveal High Spatiotemporal Variation and the Heavy‐Tail Characteristic of Nitrous Oxide Emissions in Iowa

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Remote Sensing Soil Freeze‐Thaw Status and North American N2O Emissions From a Regional Inversion

Cited by 4 publications

References 37 publications

Overwinter and Spring Thaw Nitrous Oxide Fluxes in a Northern Prairie Cropland Are Limited but a Significant Proportion of Annual Emissions

Overwinter and Spring Thaw Nitrous Oxide Fluxes in a Northern Prairie Cropland Are Limited but a Significant Proportion of Annual Emissions

Top-down constraints on N2O emissions from Canada

Airborne Measurements Reveal High Spatiotemporal Variation and the Heavy‐Tail Characteristic of Nitrous Oxide Emissions in Iowa

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Product

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Remote Sensing Soil Freeze‐Thaw Status and North American N₂O Emissions From a Regional Inversion