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FLUXNET-CH4: a global, multi-ecosystem datasetand analysis of methane seasonalityfrom freshwater wetlands

Sara Helen Knox Ma Carmelita R Alberto Jaclyn Hatala Matthes Camilo Rey Sanchez Guan Xhuan Wong Kyle B Delwiche Sara Helen Knox Avni Malhotra Etienne Fluet-Chouinard Gavin Mcnicol Sarah Feron Zutao Ouyang Dario Papale Carlo Trotta Eleonora Canfora you-Wei Cheah Danielle Christianson Ma. Carmelita R. Alberto Pavel Alekseychik Mika Aurela Dennis Baldocchi Sheel Bansal David P Billesbach Gil Bohrer Rosvel Bracho Nina Buchmann David I Campbell Gerardo Celis Jiquan Chen Weinan Chen Housen Chu Higo J Dalmagro Sigrid Dengel Ankur R Desai Matteo Detto Han Dolman Elke Eichelmann Eugenie Euskirchen Daniela Famulari Kathrin Fuchs Mathias Goeckede Sébastien Gogo 1, 2 Mangaliso J Gondwe Jordan P Goodrich Pia Gottschalk Scott L Graham Martin Heimann Manuel Helbig Carole Helfter Kyle S Hemes Takashi Hirano David Hollinger Lukas Hörtnagl Hiroki Iwata Adrien Jacotot Gerald Jurasinski Minseok Kang Kuno Kasak John King Janina Klatt Franziska Koebsch Ken W Krauss Derrick y F Lai Annalea Lohila Ivan Mammarella Luca Belelli Marchesini Giovanni Manca Jaclyn Hatala Matthes Trofim Maximov Lutz Merbold Bhaskar Mitra Timothy H Morin Eiko Nemitz Mats B Nilsson Shuli Niu Walter C Oechel Patricia y Oikawa Keisuke Ono Matthias Peichl Olli Peltola Michele L Reba Andrew D Richardson William Riley Benjamin R K Runkle youngryel Ryu Torsten Sachs Ayaka Sakabe Camilo Rey Sanchez Edward A Schuur Karina V R Schäfer Oliver Sonnentag Jed P Sparks Ellen Stuart-Haëntjens Cove Sturtevant Ryan C Sullivan Daphne J Szutu Jonathan E Thom Margaret S Torn Eeva-Stiina Tuittila Jessica Turner Masahito Ueyama Alex C Valach Rodrigo Vargas Andrej Varlagin Alma Vazquez-Lule Joseph G Verfaillie Timo Vesala George L Vourlitis Eric J Ward Christian Wille Georg Wohlfahrt Guan Xhuan Wong Zhen Zhang Donatella Zona Lisamarie Windham-Myers Benjamin Poulter Robert B Jackson 
2 Biogéosystèmes Continentaux - UMR7327
ISTO - Institut des Sciences de la Terre d'Orléans - UMR7327 : UMR7327
Abstract : Abstract. Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions due to quasi-continuous and high-temporal-resolution CH4 flux measurements, coincident carbon dioxide, water, and energy flux measurements, lack of ecosystem disturbance, and increased availability of datasets over the last decade. Here, we (1) describe the newly published dataset, FLUXNET-CH4 Version 1.0, the first open-source global dataset of CH4 EC measurements (available at, last access: 7 April 2021). FLUXNET-CH4 includes half-hourly and daily gap-filled and non-gap-filled aggregated CH4 fluxes and meteorological data from 79 sites globally: 42 freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained ecosystems, 7 rice paddy sites, 2 lakes, and 15 uplands. Then, we (2) evaluate FLUXNET-CH4 representativeness for freshwater wetland coverage globally because the majority of sites in FLUXNET-CH4 Version 1.0 are freshwater wetlands which are a substantial source of total atmospheric CH4 emissions; and (3) we provide the first global estimates of the seasonal variability and seasonality predictors of freshwater wetland CH4 fluxes. Our representativeness analysis suggests that the freshwater wetland sites in the dataset cover global wetland bioclimatic attributes (encompassing energy, moisture, and vegetation-related parameters) in arctic, boreal, and temperate regions but only sparsely cover humid tropical regions. Seasonality metrics of wetland CH4 emissions vary considerably across latitudinal bands. In freshwater wetlands (except those between 20∘ S to 20∘ N) the spring onset of elevated CH4 emissions starts 3 d earlier, and the CH4 emission season lasts 4 d longer, for each degree Celsius increase in mean annual air temperature. On average, the spring onset of increasing CH4 emissions lags behind soil warming by 1 month, with very few sites experiencing increased CH4 emissions prior to the onset of soil warming. In contrast, roughly half of these sites experience the spring onset of rising CH4 emissions prior to the spring increase in gross primary productivity (GPP). The timing of peak summer CH4 emissions does not correlate with the timing for either peak summer temperature or peak GPP. Our results provide seasonality parameters for CH4 modeling and highlight seasonality metrics that cannot be predicted by temperature or GPP (i.e., seasonality of CH4 peak). FLUXNET-CH4 is a powerful new resource for diagnosing and understanding the role of terrestrial ecosystems and climate drivers in the global CH4 cycle, and future additions of sites in tropical ecosystems and site years of data collection will provide added value to this database. All seasonality parameters are available at (Delwiche et al., 2021). Additionally, raw FLUXNET-CH4 data used to extract seasonality parameters can be downloaded from (last access: 7 April 2021), and a complete list of the 79 individual site data DOIs is provided in Table 2 of this paper.
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Submitted on : Monday, September 6, 2021 - 2:03:10 PM
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Sara Helen Knox, Ma Carmelita R Alberto, Jaclyn Hatala Matthes, Camilo Rey Sanchez, Guan Xhuan Wong, et al.. FLUXNET-CH4: a global, multi-ecosystem datasetand analysis of methane seasonalityfrom freshwater wetlands. Earth System Science Data, Copernicus Publications, 2021, 13 (7), pp.3607-3689. ⟨10.5194/essd-13-3607-2021⟩. ⟨insu-03335685⟩



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