Aircraft-based inversions quantify the importance of wetlands and livestock for Upper Midwest methane emissions.

Autor:	Yu X; Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, Minnesota 55108, United States., Millet DB; Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, Minnesota 55108, United States., Wells KC; Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, Minnesota 55108, United States., Henze DK; Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States., Cao H; Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States., Griffis TJ; Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, Minnesota 55108, United States., Kort EA; Climate and Space Sciences and Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States., Plant G; Climate and Space Sciences and Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States., Deventer MJ; Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, Minnesota 55108, United States.; ANECO Institut für Umweltschutz GmbH & Co, 21079 Hamburg, Germany., Kolka RK; Northern Research Station, US Department of Agriculture Forest Service, Grand Rapids, Minnesota 55744, United States., Roman DT; Northern Research Station, US Department of Agriculture Forest Service, Grand Rapids, Minnesota 55744, United States., Davis KJ; Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Desai AR; Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Baier BC; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States.; Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States., McKain K; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States.; Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States., Czarnetzki AC; Department of Earth and Environmental Sciences, University of Northern Iowa, Cedar Falls, Iowa 50614, United States., Bloom AA; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, United States.
Jazyk:	angličtina
Zdroj:	Atmospheric chemistry and physics [Atmos Chem Phys] 2021 Jan; Vol. 21 (2), pp. 951-971. Date of Electronic Publication: 2021 Jan 25.
DOI:	10.5194/acp-21-951-2021
Abstrakt:	We apply airborne measurements across three seasons (summer, winter and spring 2017-2018) in a multi-inversion framework to quantify methane emissions from the US Corn Belt and Upper Midwest, a key agricultural and wetland source region. Combing our seasonal results with prior fall values we find that wetlands are the largest regional methane source (32 %, 20 [16-23] Gg/d), while livestock (enteric/manure; 25 %, 15 [14-17] Gg/d) are the largest anthropogenic source. Natural gas/petroleum, waste/landfills, and coal mines collectively make up the remainder. Optimized fluxes improve model agreement with independent datasets within and beyond the study timeframe. Inversions reveal coherent and seasonally dependent spatial errors in the WetCHARTs ensemble mean wetland emissions, with an underestimate for the Prairie Pothole region but an overestimate for Great Lakes coastal wetlands. Wetland extent and emission temperature dependence have the largest influence on prediction accuracy; better representation of coupled soil temperature-hydrology effects is therefore needed. Our optimized regional livestock emissions agree well with the Gridded EPA estimates during spring (to within 7 %) but are ∼25 % higher during summer and winter. Spatial analysis further shows good top-down and bottom-up agreement for beef facilities (with mainly enteric emissions) but larger (∼30 %) seasonal discrepancies for dairies and hog farms (with >40 % manure emissions). Findings thus support bottom-up enteric emission estimates but suggest errors for manure; we propose that the latter reflects inadequate treatment of management factors including field application. Overall, our results confirm the importance of intensive animal agriculture for regional methane emissions, implying substantial mitigation opportunities through improved management. Competing Interests: Competing interests. The authors declare that they have no conflict of interest.
Databáze:	MEDLINE
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