Browsing by Author "Jones, Anna E."

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    Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights
    (The Royal Society, 2021-12-06) MOYA/ZWAMPS Team; Nisbet, Euan; Allen, Grant; Fisher, Rebecca E.; France, James L.; Lee, James D.; Lowry, David; Andrade, Marcos F.; Bannan, Thomas J.; Barker, Patrick; Bateson, Prudence; Bauguitte, Stéphane J.-B.; Bower, Keith N.; Broderick, Tim J.; Chibesakunda, Francis; Cain, Michelle; Cozens, Alice E.; Daly, Michael C.; Ganesan, Anita L.; Jones, Anna E.; Lambakasa, Musa; Lunt, Mark F.; Mehra, Archit; Moreno, Isabel; Pasternak, Dominika; Palmer, Paul I.; Percival, Carl J.; Pitt, Joseph R.; Riddle, Amber J.; Rigby, Matthew; Shaw, Jacob T.; Stell, Angharad C.; Vaughan, Adam R.; Warwick, Nicola J.; Wilde, Shona E.
    We report methane isotopologue data from aircraft and ground measurements in Africa and South America. Aircraft campaigns sampled strong methane fluxes over tropical papyrus wetlands in the Nile, Congo and Zambezi basins, herbaceous wetlands in Bolivian southern Amazonia, and over fires in African woodland, cropland and savannah grassland. Measured methane δ13CCH4 isotopic signatures were in the range −55 to −49‰ for emissions from equatorial Nile wetlands and agricultural areas, but widely −60 ± 1‰ from Upper Congo and Zambezi wetlands. Very similar δ13CCH4 signatures were measured over the Amazonian wetlands of NE Bolivia (around −59‰) and the overall δ13CCH4 signature from outer tropical wetlands in the southern Upper Congo and Upper Amazon drainage plotted together was −59 ± 2‰. These results were more negative than expected. For African cattle, δ13CCH4 values were around −60 to −50‰. Isotopic ratios in methane emitted by tropical fires depended on the C3 : C4 ratio of the biomass fuel. In smoke from tropical C3 dry forest fires in Senegal, δ13CCH4 values were around −28‰. By contrast, African C4 tropical grass fire δ13CCH4 values were −16 to −12‰. Methane from urban landfills in Zambia and Zimbabwe, which have frequent waste fires, had δ13CCH4 around −37 to −36‰. These new isotopic values help improve isotopic constraints on global methane budget models because atmospheric δ13CCH4 values predicted by global atmospheric models are highly sensitive to the δ13CCH4 isotopic signatures applied to tropical wetland emissions. Field and aircraft campaigns also observed widespread regional smoke pollution over Africa, in both the wet and dry seasons, and large urban pollution plumes. The work highlights the need to understand tropical greenhouse gas emissions in order to meet the goals of the UNFCCC Paris Agreement, and to help reduce air pollution over wide regions of Africa. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.
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    Understanding sources and drivers of size-resolved aerosol in the High Arctic islands of Svalbard using a receptor model coupled with machine learning
    (American Chemical Society, 2022-07-25) Song, Congbo; Becagli, Silvia; Beddows, David C. S.; Brean, James; Browse, Jo; Dai, Qili; Dall'Osto, Manuel; Ferracci, Valerio; Harrison, Roy M.; Harris, Neil; Li, Weijun; Jones, Anna E.; Kirchgäßner, Amelie; Kramawijaya, Agung Ghani; Kurganskiy, Alexander; Lupi, Angelo; Mazzola, Mauro; Severi, Mirko; Traversi, Rita; Shi, Zongbo
    Atmospheric aerosols are important drivers of Arctic climate change through aerosol–cloud–climate interactions. However, large uncertainties remain on the sources and processes controlling particle numbers in both fine and coarse modes. Here, we applied a receptor model and an explainable machine learning technique to understand the sources and drivers of particle numbers from 10 nm to 20 μm in Svalbard. Nucleation, biogenic, secondary, anthropogenic, mineral dust, sea salt and blowing snow aerosols and their major environmental drivers were identified. Our results show that the monthly variations in particles are highly size/source dependent and regulated by meteorology. Secondary and nucleation aerosols are the largest contributors to potential cloud condensation nuclei (CCN, particle number with a diameter larger than 40 nm as a proxy) in the Arctic. Nonlinear responses to temperature were found for biogenic, local dust particles and potential CCN, highlighting the importance of melting sea ice and snow. These results indicate that the aerosol factors will respond to rapid Arctic warming differently and in a nonlinear fashion.