FLUXNET-CH4 Synthesis Activity

Objectives, Observations, and Future Directions

FLUXNET methane (CH4) is an initiative led by the Global Carbon Project, in close partnership with AmeriFlux and EuroFlux, to compile a global database of existing eddy covariance CH4 flux measurements (Knox et al., 2019). Our approach is to include all currently available and future CH4 flux tower observations in a global CH4 database, including freshwater, coastal, natural and managed ecosystems, as well as upland ecosystems that may be measuring CH4 flux uptake by soils. The initiative is open to all members of the EC community. Database compilation began in 2017 and is ongoing. Currently we have compiled data from 60 of the ~110 sites currently committed to participating in our FLUXNET-CH4 activity (Figure 1, Table 1) (Knox et al., 2019). We are continuing to engage the EC community more broadly to expand the database in the future. For participants interested in joining this effort, data from sites in the Americas can be submitted to AmeriFlux; otherwise, data can be submitted to the European Fluxes Database Cluster.

Figure 1. Location of the 200 tower sites that report eddy covariance CH4 flux measurements worldwide. Triangles indicate sites from which data are included in this manuscript, with circles indicating additional flux towers measuring CH4 emissions. The colors of the markers represent the vegetation type based on the International Geosphere-Biosphere Programme (IGBP) definition. See Table S1 from Knox et al., 2019 for a list of sites, their characteristics, and years of operation. Sites are overlaid over a map of the differences between the average CH4 emissions over 2000-2010 between top-down and bottom-up wetland CH4 estimates. Top-down estimates are represented by the natural fluxes inventoried in NOAA’s CarbonTracker. Bottom-up emissions were produced from an ensemble of 11 Earth System Models simulations (Poulter et al. 2017).

In addition to many applications, an ultimate goal of the FLUXNET-CH4 activity is to generate a publicly available, open-access, data-driven global CH4 emissions product using similar machine-learning-based approaches used by FluxCom for CO2, water and energy fluxes. This gridded product is being developed in partnership with the Stanford Machine Learning Group and AI for Climate Change Bootcamp. This gridded product will provide an independent bottom-up estimate of global wetland CH4 emissions to compare with estimates of global CH4 emissions from land-surface models and atmospheric inversions. Recent work has shown the potential to upscale EC CH4 flux observations across northern wetlands (Peltola et al., 2019), however, our objective is to expand this to a globally gridded product.

The near continuous, high-frequency nature of EC measurements also offers significant promise for improving our understanding of ecosystem-scale CH4 flux dynamics. As such, through a USGS Powell Center Working Group we are also exploring the dominant controls on net ecosystem-scale CH4 fluxes across wetlands globally (Knox et al., 2019), and investigating the scale-emergent, nonlinear, and lagged processes of CH4 exchange. Through this activity, we are also utilizing the global CH4 database to parameterize and benchmark the performance of land-surface models of global CH4 emissions, as this dataset provides a unique opportunity for informing and validating biogeochemical models.


FLUXNET-CH4 Contributors

Sara H. Knox,   Robert B. Jackson,   Benjamin Poulter,   Gavin McNicol,   Etienne Fluet-Chouinard,   Zhen Zhang,   Gustaf Hugelius,   Philippe Bousquet,   Josep G. Canadell,   Marielle Saunois,   Dario Papale,   Housen Chu,   Trevor F. Keenan,   Dennis Baldocchi,   Margaret S.Torn,   Ivan Mammarella,   Carlo Trotta 

Current Site PIs – 60 Sites; 66 Contributors; 54 Institutions

Mika Aurela,   Gil Bohrer,   David I. Campbell,   Alessandro Cescatti,   Samuel Chamberlain,   Jiquan Chen,   Weinan Chen,   Sigrid Dengel,   Ankur R. Desai,   Eugenie Euskirchen,   Thomas Friborg,   Daniele Gasbarra,   Ignacio Goded,  Mathias Goeckede,   Martin Heimann,   Manuel Helbig,   Takashi Hirano,   David Y. Hollinger,   Hiroki Iwata,   Minseok Kang,   Janina Klatt,   Ken W. Krauss,   Lars Kutzbach,   Annalea Lohila,   Bhaskar Mitra,   Timothy H. Morin,   Mats B. Nilsson,   Shuli Niu,   Asko Noormets,   Walter C. Oechel,   Matthias Peichl,   Olli Peltola,   Michele L. Reba,   Andrew D. Richardson,   Benjamin R. K. Runkle,   Youngryel Ryu,   Torsten Sachs,   Karina V. R. Schäfer,  Hans Peter Schmid,   Narasinha Shurpali,   Oliver Sonnentag,   Angela C. I. Tang,   Masahito Ueyama,   Rodrigo Vargas,   Timo Vesala,   Eric J. Ward,   Lisamarie Windham-Myers,   Georg Wohlfahrt,   Donatella Zona

This work is supported by the Gordon and Betty Moore Foundation, the USGS Powell Synthesis Center, AmeriFlux, the European Fluxes Database Cluster, and FLUXNET


  • Knox, S. H., Jackson, R., Poulter, B., et al. (2019). FLUXNET-CH4 Synthesis Activity: Objectives, Observations, and Future Directions. Bulletin of the American Meteorological Society, Accepted.
  • Peltola, O., Vesala, T., Gao, Y., et al. (2019). Monthly Gridded Data Product of Northern Wetland Methane Emissions Based on Upscaling Eddy Covariance Observations. Earth System Science Data Discussions. https://doi.org/10.5194/essd-2019-28
  • Poulter, B., Bousquet, P., Canadell, J. G., et al. (2017). Global wetland contribution to 2000–2012 atmospheric methane growth rate dynamics. Environmental Research Letters, 12(9), 094013. https://doi.org/10.1088/1748-9326/aa8391

Sites currently included in the database

Table 1. Characteristics of sites currently included in the database. Ecosystem type is based on the classification of Olefeldt et al. (2013) and Treat et al. (2018). Biome was based on the classification of Olson et al. (2001) and extracted using site coordinates. Vegetation type was based on the International Geosphere-Biosphere Programme (IGBP) definition. Salinity regime includes freshwater (FW) or saltwater (SW) wetlands. Disturbance is based on the classification of Turetsky et al. (2014). Data from all sites are publicly available, primarily through Ameriflux and the European Database Cluster, and in a few cases, through other databases/repositories. Site DOIs are specified where applicable.

Site IDSite NameCountryLatLongBiomeIGBPEcosystem TypeSalinityWetland DisturbanceSite PIdata DOI/Location
US-ICsWet sedge tundraUSA68.606-149.311TundraWETWet tundraFWUndisturbedEugenie Euskirchendoi: 10.17190/AM F/1246130
SE-St1Stordalen grassland (Mire)Sweden68.3519.05TundraWETFenFWUndisturbedThomas FriborgEuropean Fluxes Database Cluster
SE-StoStordalen Palsa BogSweden68.35619.05TundraWETBogFWUndisturbedThomas FriborgEuropean Fluxes Database Cluster
RU-VrkSeida/VorkutaRussia67.05562.94TundraWETWet tundraFWUndisturbedThomas FriborgEuropean Fluxes Database Cluster
RU-Ch2Chersky referenceRussia68.617161.351TundraWETWet tundraFWUndisturbedMatthias GoeckedeEuropean Fluxes Database Cluster
RU-CheCherskyRussia68.613161.341TundraWETWet tundraFWDryingMatthias GoeckedeEuropean Fluxes Database Cluster
RU-SAMSamoylovRussia72.374126.496TundraWETWet tundraFWUndisturbedTorsten SachsEuropean Fluxes Database Cluster
US-NGBNGEE BarrowUSA71.28-156.609TundraWETWet tundraFWUndisturbedMargaret Torndoi: 10.17190/AM F/1436326
US-BeoBarrowUSA71.281-156.612TundraWETWet tundraFWUndisturbedDonatella ZonaAmeriflux
US-BesBarrowUSA71.281-156.596TundraWETWet tundraFWUndisturbedDonatella ZonaAmeriflux
US-AtqAtqasukUSA70.47-157.409TundraWETWet tundraFWUndisturbedDonatella Zonadoi:10.17190/AMF/1246029
US-IvoIvotukUSA68.486-155.75TundraWETWet tundraFWUndisturbedDonatella Zonadoi:10.17190/AMF/1246067
US-BZSBlack spruce forestUSA64.7-148.32Boreal Forests/TaigaENFUpland----Eugenie Euskirchenhttp://www.lter.uaf.edu/data/data-detail/id/708
US-BZFRich FenUSA64.704-148.313Boreal Forests/TaigaWETFenFWUndisturbedEugenie Euskirchenhttp://www.lter.uaf.edu/data/data-detail/id/708
US-BZoThermokarst collapse scar bogUSA64.7-148.32Boreal Forests/TaigaWETBogFWUndisturbedEugenie Euskirchenhttp://www.lter.uaf.edu/data/data-detail/id/708
FI-LomLompolojankkaFinland67.99724.209Boreal Forests/TaigaWETFenFWUndisturbedAnnalea LohilaEuropean Fluxes Database Cluster
SE-DegDegeroSweden64.18219.557Boreal Forests/TaigaWETFenFWUndisturbedMatthias Peichl, Mats NilssonEuropean Fluxes Database Cluster
CA-SCCScotty Creek - Peat plateau/collapse scarCanada61.308-121.299Boreal Forests/TaigaENFPeat plateauFW--Oliver Sonnentagdoi:10.17190/AMF/1480303
CA-SCBScotty Creek BogCanada61.309-121.299Boreal Forests/TaigaWETBogFWUndisturbedOliver SonnentagAmeriflux
US-NGCNGEE Arctic CouncilUSA64.861-163.701Boreal Forests/TaigaWETWet tundraFWUndisturbedMargaret TornAmeriflux
US-UafUniversity of Alaska, FairbanksUSA64.866-147.856Boreal Forests/TaigaWETBogFWUndisturbedMasahito Ueyamadoi:10.17190/AMF/1480322
FI-SiiSiikaneva I (FI-Sii)Finland61.83324.193Boreal Forests/TaigaWETFenFWUndisturbedTimo Vesala & Ivan MammarellaEuropean Fluxes Database Cluster
FI-Si2Siikaneva IIFinland61.83724.17Boreal Forests/TaigaWETBogFWUndisturbedTimo Vesala & Ivan MammarellaEuropean Fluxes Database Cluster
US-MybMayberry WetlandUSA38.05-121.765TemperateWETMarshFWWettingDennis Baldocchidoi: 10.17190/AM F/1246139
US-SneSherman Island Restored WetlandUSA38.037-121.755TemperateWETMarshFWWettingDennis Baldocchidoi: 10.17190/AM F/1418684
US-Tw1Twitchell West Pond WetlandUSA38.107-121.647TemperateWETMarshFWWettingDennis Baldocchidoi: 10.17190/AM F/1246147
US-Tw4Twitchell East End WetlandUSA38.103-121.641TemperateWETMarshFWWettingDennis Baldocchidoi: 10.17190/AM F/1246148
US-TwtTwitchell RiceUSA38.109-121.653TemperateCRO - RiceRiceFW--Dennis Baldocchidoi: 10.17190/AM F/1246151
US-Bi2Bouldin Island cornUSA38.109-121.535TemperateCRO - OtherDrained/Agricultural wetlandFWDryingDennis Baldocchidoi: 10.17190/AM F/1419513
US-Bi1Bouldin Island AlfalfaUSA38.102-121.504TemperateCRO - OtherDrained/Agricultural wetlandFWDryingDennis Baldocchidoi:10.17190/AMF/1480317
US-SndSherman IslandUSA38.037-121.754TemperateCRO - OtherDrained/Agricultural wetlandFWDryingDennis Baldocchidoi: 10.17190/AM F/1246094
US-OWCOld Woman CreekUSA41.38-82.512TemperateWETMarshFWUndisturbedGil Bohrerdoi: 10.17190/AM F/1246094
US-ORvOlentangy River Wetland Research ParkUSA40.02-83.018TemperateWETMarshFWUndisturbedGil Bohrerdoi:10.17190/AMF/1246135
NZ-KopKopuataiNew Zealand-37.388175.554TemperateWETBogFWUndisturbedDave Campbellhttps://researchcommons.waikato.ac.nz/handle/10289/11393
IT-CasCastellaroItaly45.078.718TemperateCRO - RiceRiceFW--Alessandro CescattiEuropean Fluxes Database Cluster
US-WPTWinous Point North MarshUSA41.465-82.996TemperateWETMarshFWWettingJiquan Chen & Housen Chudoi: 10.17190/AM F/1246155
US-CRTCurtice Walter-Berger croplandUSA41.628-83.347TemperateCRO - OtherUpland----Jiquan Chen & Housen Chudoi: 10.17190/AM F/1246156
US-LosLost CreekUSA46.083-89.979TemperateWETFenFWUndisturbedAnkur Desaidoi: 10.17190/AM F/1246071
JP-MseMase paddy flux site (MSE)Japan36.054140.027TemperateCRO - RiceRiceFW--Akira MiyataEuropean Fluxes Database Cluster
JP-SwlSuwa Lake Sitejapan36.047138.108TemperateWATWaterbodyFWUndisturbedHiroki IwataEuropean Fluxes Database Cluster
IT-BCiBorgo CioffiItaly40.52414.957TemperateCRO - OtherUpland----Vincenzo MagliuloEuropean Fluxes Database Cluster
CN-HguHongyuanChina32.8102.55TemperateGRAUpland----Shuli NiuEuropean Fluxes Database Cluster
US-NC4NC Alligator RiverUSA35.788-75.904TemperateWETSwampFWUndisturbedAsko Noormetsdoi:10.17190/AMF/1480314
DE-SfNSchechenfilz NordGermany47.80611.328TemperateWETBogFWUndisturbedHans Peter SchmidEuropean Fluxes Database Cluster
US-Ho1Howland Forest (main tower)USA45.204-68.74TemperateENFUpland----Andrew Richardsondoi:10.17190/AMF/1246061
US-HRAHumnoke Farm Rice Field AWD, United StatesUSA34.585-91.752TemperateCRO - RiceRiceFW--Benjamin RunkleAmeriflux
US-HRCHumnoke Farm Rice Field conventional, United StatesUSA34.589-91.752TemperateCRO - RiceRiceFW--Benjamin RunkleAmeriflux
KR-CRKCheorwon Rice paddySouth Korea38.201127.251TemperateCRO - RiceRiceFW--Youngryel Ryu & Minseok KangEuropean Fluxes Database Cluster
DE-ZrkZarnekowGermany53.87612.889TemperateWETFenFWWettingTorsten SachsEuropean Fluxes Database Cluster
DE-DgwDagowseeGermany53.15113.054TemperateWATWaterbodyFWUndisturbedTorsten SachsEuropean Fluxes Database Cluster
US-MRMMarsh Resource Meadowlands Mitigation BankUSA40.816-74.044TemperateWETSalt MarshSWWettingKarina SchäferAmeriflux
--Bog Lake peatlandUSA47.53-93.47TemperateWETFenFWUndisturbedShahi VermaAmeriflux
--MacArthur Agro-Ecology Research CenterUSA27.163-81.187TemperateCRO - OtherDrained/Agricultural wetlandFWDryingJed Sparks & Samuel ChamberlainAmeriflux
JP-BBYBibai bogJapan43.323141.811TemperateWETBogFWUndisturbedMasahito UeyamaEuropean Fluxes Database Cluster
US-StJSt Jones ReserveUSA39.088-75.437TemperateWETSalt MarshSWUndisturbedRodrigo Vargasdoi:10.17190/AMF/1480316
US-SrrSuisun marsh - Rush RanchUSA38.201-122.026TemperateWETSalt MarshSWUndisturbedLisamarie Windham-Myersdoi:10.17190/AMF/1418685
AT-NeuNeustiftAustria47.11711.318TemperateGRAUpland----Georg WohlfahrtEuropean Fluxes Database Cluster
US-LA2Salvador WMA Freshwater MarshUSA29.859-90.287Tropical & SubtropicalWETMarshFWUndisturbedKen KraussAmeriflux
US-LA1Pointe-aux-Chenes Brackish MarshUSA29.501-90.445Tropical & SubtropicalWETSalt MarshSWUndisturbedKen KraussAmeriflux
MY-MLMMaludamMalaysia1.454111.149Tropical & SubtropicalWETSwampFWUndisturbedAngela Tanghttps://doi.org/10.5281/zenodo.1161966