Abstract
Mapping in situ eddy covariance measurements of terrestrial land–atmosphere fluxes to the globe is a key method for diagnosing the Earth system from a data-driven perspective. We describe the first global products (called X-BASE) from a newly implemented upscaling framework, FLUXCOM-X, representing an advancement from the previous generation of FLUXCOM products in terms of flexibility and technical capabilities. The X-BASE products are comprised of estimates of CO2 net ecosystem exchange (NEE), gross primary productivity (GPP), evapotranspiration (ET), and for the first time a novel, fully data-driven global transpiration product (ETT), at high spatial (0.05°) and temporal (hourly) resolution. X-BASE estimates the global NEE at −5.75 ± 0.33 Pg C yr−1 for the period 2001–2020, showing a much higher consistency with independent atmospheric carbon cycle constraints compared to the previous versions of FLUXCOM. The improvement of global NEE was likely only possible thanks to the international effort to increase the precision and consistency of eddy covariance collection and processing pipelines, as well as to the extension of the measurements to more site years resulting in a wider coverage of bioclimatic conditions. However, X-BASE global net ecosystem exchange shows a very low interannual variability, which is common to state-of-the-art data-driven flux products and remains a scientific challenge. With 125 ± 2.1 Pg C yr−1 for the same period, X-BASE GPP is slightly higher than previous FLUXCOM estimates, mostly in temperate and boreal areas. X-BASE evapotranspiration amounts to 74.7 × 103 ± 0.9×103 km3 globally for the years 2001–2020 but exceeds precipitation in many dry areas, likely indicating overestimation in these regions. On average 57 % of evapotranspiration is estimated to be transpiration, in good agreement with isotope-based approaches, but higher than estimates from many land surface models. Despite considerable improvements to the previous upscaling products, many further opportunities for development exist. Pathways of exploration include methodological choices in the selection and processing of eddy covariance and satellite observations, their ingestion into the framework, and the configuration of machine learning methods. For this, the new FLUXCOM-X framework was specifically designed to have the necessary flexibility to experiment, diagnose, and converge to more accurate global flux estimates.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Biogeosciences |
| Vol/bind | 21 |
| Udgave nummer | 22 |
| Sider (fra-til) | 5079-5115 |
| Antal sider | 37 |
| ISSN | 1726-4170 |
| DOI | |
| Status | Udgivet - 2024 |
Bibliografisk note
Funding Information:The work of Sophia Walther, Jacob A. Nelson, and Martin Jung was funded in part by the European Union's Horizon 2020 research and innovation program (grant nos. 776186 CHE, 776810 VERIFY, 958927 CoCO2, 820852 E-SHAPE). Sophia Walther acknowledges funding from a European Space Agency Living Planet Fellowship in the project Vad3e mecum as well as the CCI LST project (4000123553/18/I-NB). Gregory Duveiller and Zayd Mahmoud Hamdi acknowledge funding from the European Space Agency in the Sen4GPP project (4000134598/21/I-NB). Simone Sabbatini and Gregory Duveiller acknowledge Horizon Europe funding (Open-Earth-Monitor Cyberinfrastructure project, 101059548). Donatella Zona acknowledges NSF award numbers 2149988 and 1932900. Anne Klosterhalfen and Alexander Knohl acknowledge funding by the German Federal Ministry of Education and Research (BMBF) as part of the European Integrated Carbon Observation System (ICOS), by the Deutsche Forschungsgemeinschaft (INST 186/1118-1 FUGG) and by the Ministry of Lower Saxony for Science and Culture (DigitalForst: Nieders\u00E4chsisches Vorab (ZN 3679)). Leonardo Montagnani acknowledges funding provided by Forest Services, Autonomous Province of Bolzano. Enrico A. Yepez acknowledges that MX-Tes is part of the MexFlux regional network. Funding for the Swiss sites is greatly acknowledged from various sources: from the EU project SUPER-G (contract no. 774124), the SNF projects M4P (40FA40_154245), DiRad (146373), InnoFARM (407340_172433), CoCo (200021_197357), ICOS-CH (20FI21_148992, 20FI20_173691, 20FI20_198227), and InsuranceGrass (100018L_200918); from NESTLE via the ETH foundation (DONA); and from the ETH Board and from ETH Zurich (project FEVER ETH-27 19-1). Funding for US-BZB, US-BZF, US-BZo, and US-BZB was provided by National Science Foundation grant nos. DEB LTREB 1354370 and 2011257, DEB-0425328, DEB-0724514, and DEB-0830997, as well as funding by the US Geological Survey Climate R&D program. Bonanza Creek Long Term Experimental Research station provided lab space and equipment. US-ICs and US-ICt were supported by grants from the Arctic Observatory Program of the National Science Foundation (grant nos. 1936752, 1503912, 1107892). Sergio Aranda-Barranco acknowledges projects PID2020-117825GB-C21 and PID2020-117825GB-C22 funded by MCIN/AEI/10.13039/501100011033, as well as support by the FPU grant by the Ministry of Universities of Spain (REF: FPU19/01647). SE-Deg, SE-Svb, and SE-Ros acknowledge funding from the Swedish Research Council and contributions from research institutes to the Swedish Integrated Carbon Observation System (ICOS-Sweden) Research Infrastructure and the Swedish Infrastructure for Ecosystem Science (SITES). Torbern Tagesson was funded by the Swedish National Space Agency (SNSA Dnr 2021-00144) and FORMAS (Dnr. 2021-00644). William Woodgate is supported by an Australian Research Council DECRA Fellowship (DE190101182). Ivan Mammarella acknowledges funding from Academy of Finland (N-PERM 341349), ICOS-Finland UH, and EU projects (GreenFeedBack 101056921, LiWeFor). Domenico Vitale acknowledges the Integrated Carbon Observation System \u2013 Research Infrastructure (ICOS ERIC, https://www.icos-cp.eu/ , last access: 3 October 2024) and the ICOS ETC funding from the Italian Ministry of Research. Mathias G\u00F6ckede was supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 951288, Q-Arctic). The DE-Geb site received funds within the ICOS Germany preparatory and implementation phase by the Federal Ministry of Education and Research and is supported by the Ministry of Digital and Traffic through ICOS station contributions as well as by the Ministry of Food and Agriculture covering operational costs. Giacomo A. Gerosa thanks the Catholic University of Brescia for continuous supporting the research station of Bosco Fontana (ICOS station IT-Bft). Ladislav \u0160igut acknowledges support by the Ministry of Education, Youth and Sports of CR within the CzeCOS program (grant number LM2023048) and the AdAgriF project (CZ.02.01.01/00/22_008/0004635). Gustau Camps-Valls, Markus Reichstein, Basil Kraft, and Gregory Duveiller acknowledge funding by the European Research Council (ERC) Synergy Grant \u201CUnderstanding and modeling the Earth System with Machine Learning (USMILE)\u201D under the European Union's Horizon 2020 research and innovation program (grant agreement no. 855187). Ankur Desai acknowledges the US Department of Energy American Network Management Project award to the ChEAS core site cluster (US-PFa, US-WCr, US-Syv, US-Los), Wisconsin Potato and Vegetable Growers Association, and WI Department of Natural Resources (US-CS), and NSF grant nos. 1822420, 2313772 (US-PFa). Marilyn Roland and Bert Gielen acknowledge the Research Foundation Flanders (FWO) for the support of ICOS research infrastructure in Flanders, Belgium. Dario Papale thanks the support of the ITINERIS \u2013 Italian Integrated Environmental Research Infrastructures System project (IR0000032) funded by NextGenerationEU Mission 4.2.3.1. Timo Vesala acknowledges ICOS-Finland (University of Helsinki) and Flagship funding (grant no. 337549). Torsten Sachs acknowledges that the DE-Zrk site relies on infrastructure of the Terrestrial Environmental Observatories Network (TERENO) supported by a Helmholtz Young Investigators Grant (VH-NG-821). Elise Pendall acknowledges Australian Terrestrial Ecosystem Research Network, as part of the National Cooperative Research Infrastructure System. Sara Knox was also supported by an NSERC Discovery Grant (RGPIN-2019-04199) and an Alliance Grant (ALLRP 555468-20). Hideki Kobayashi acknowledges ArCSII no. JPMXD1420318865 (US-Prr). Stefan Metzger acknowledges the National Ecological Observatory Network, which is a program sponsored by the National Science Foundation and operated under cooperative agreement by Battelle. This material is based in part on work supported by the National Science Foundation through the NEON Program. Bernard Heinesch and Caroline Vincke acknowledge the Service Public de Wallonie (SPW-DGO6) for the support of ICOS research infrastructure in Wallonia, Belgium.
Funding Information:
This research has been supported by the National Science Foundation (grant nos. 2149988, 1932900, DEB LTREB 1354370, 2011257, DEB-0425328, DEB-0724514, DEB-0830997, 1936752, 1503912, 1107892, 1822420, and 2313772), the Deutsche Forschungsgemeinschaft (grant no. INST 186/1118-1 FUGG), the Nieders\u00E4chsische Ministerium f\u00FCr Wissenschaft und Kultur (grant no. ZN 3679), the Horizon 2020 (grant nos. 774124, 951288, 855187, 958927, 776810, 820852, and 776186), the Schweizerischer Nationalfonds zur F\u00F6rderung der Wissenschaftlichen Forschung (grant nos. 40FA40_154245, 146373, 407340_172433, 200021_197357, 100018L_200918, 20FI21_148992, 20FI20_173691, and 20FI20_198227), the ETH Z\u00FCrich Foundation (grant no. DONA), the Eidgen\u00F6ssische Technische Hochschule Z\u00FCrich (grant no. FEVER ETH-27 19-1), the Agencia Estatal de Investigaci\u00F3n (grant nos. PID2020-117825GB-C21 and PID2020-117825GB-C22), the Ministerio de Universidades (grant no. FPU19/01647), the Swedish National Space Agency (grant no. 2021-00144), the Australian Research Council (grant no. DE190101182), the Research Council of Finland (grant nos. N-PERM 341349 and 337549), the Ministerstvo \u0160kolstv\u00ED, Ml\u00E1de\u017Ee a T\u011Blov\u00FDchovy (grant no. LM2023048), the Ministry of Education, Culture, Sports, Science and Technology (grant no. JPMXD1420318865), the Helmholtz Association (grant no. VH-NG-821), the Natural Sciences and Engineering Research Council of Canada (grant nos. RGPIN-2019-04199 and ALLRP 555468-20), the European Space Agency (grant nos. Vad3e mecum, 4000134598/21/I-NB, and 4000123553/18/I-NB), the Horizon Europe Framework Programme, Horizon Europe Excellent Science (grant nos. 101059548, 20FI20_173691, 101079192, and 101056921), and the Vetenskapsr\u00E5det (grant no. 2021-00644).
Funding Information:
We would like to thank the broader eddy covariance community, including FLUXNET and the associated regional networks, particularly the European Integrated Carbon Observation System (ICOS) and AmeriFlux. We also acknowledge the contributions of Andrej Varlagin and colleagues to these efforts. We thank the team at the ICOS Carbon Portal for their support in publishing the FLUXCOM-X data sets, with great thanks in particular to Ute Karstens and Zois Zogopoulos. We also thank Brendan Byrne and colleagues of Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA, for use of the OCO-2 data. The work of Sophia Walther, Jacob A. Nelson, and Martin Jung was funded in part by the European Union\u2019s Horizon 2020 research and innovation program (grant nos. 776186 CHE, 776810 VERIFY, 958927 CoCO2, 820852 E-SHAPE). Sophia Walther acknowledges funding from a European Space Agency Living Planet Fellowship in the project Vad3e mecum as well as the CCI LST project (4000123553/18/I-NB). Gregory Duveiller and Zayd Mahmoud Hamdi acknowledge funding from the European Space Agency in the Sen4GPP project (4000134598/21/I-NB). Simone Sabbatini and Gregory Duveiller acknowledge Horizon Europe funding (Open-Earth-Monitor Cyberinfrastructure project, 101059548). Donatella Zona acknowledges NSF award numbers 2149988 and 1932900. Anne Klosterhalfen and Alexander Knohl acknowledge funding by the German Federal Ministry of Education and Research (BMBF) as part of the European Integrated Carbon Observation System (ICOS), by the Deutsche Forschungsgemeinschaft (INST 186/1118-1 FUGG) and by the Ministry of Lower Saxony for Science and Culture (DigitalForst: Nieders\u00E4chsisches Vorab (ZN 3679)). Leonardo Montagnani acknowledges funding provided by Forest Services, Autonomous Province of Bolzano. Enrico A. Yepez acknowledges that MX-Tes is part of the MexFlux regional network. Funding for the Swiss sites is greatly acknowledged from various sources: from the EU project SUPER-G (contract no. 774124), the SNF projects M4P (40FA40_154245), DiRad (146373), InnoFARM (407340_172433), CoCo (200021_197357), ICOS-CH (20FI21_148992, 20FI20_173691, 20FI20_198227), and InsuranceGrass (100018L_200918); from NESTLE via the ETH foundation (DONA); and from the ETH Board and from ETH Zurich (project FEVER ETH-27 19-1). Funding for US-BZB, US-BZF, US-BZo, and US-BZB was provided by National Science Foundation grant nos. DEB LTREB 1354370 and 2011257, DEB-0425328, DEB-0724514, and DEB-0830997, as well as funding by the US Geological Survey Climate R&D program. Bonanza Creek Long Term Experimental Research station provided lab space and equipment. US-ICs and US-ICt were supported by grants from the Arctic Observatory Program of the National Science Foundation (grant nos. 1936752, 1503912, 1107892). Sergio Aranda-Barranco acknowledges projects PID2020-117825GB-C21 and PID2020-117825GB-C22 funded by MCIN/AEI/10.13039/501100011033, as well as support by the FPU grant by the Ministry of Universities of Spain (REF: FPU19/01647). SE-Deg, SE-Svb, and SE-Ros acknowledge funding from the Swedish Research Council and contributions from research institutes to the Swedish Integrated Carbon Observation System (ICOS-Sweden) Research Infrastructure and the Swedish Infrastructure for Ecosystem Science (SITES). Torbern Tagesson was funded by the Swedish National Space Agency (SNSA Dnr 2021-00144) and FORMAS (Dnr. 2021-00644). William Woodgate is supported by an Australian Research Council DECRA Fellowship (DE190101182). Ivan Mammarella acknowledges funding from Academy of Finland (N-PERM 341349), ICOS-Finland UH, and EU projects (GreenFeedBack 101056921, LiWeFor). Domenico Vitale acknowledges the Integrated Carbon Observation System \u2013 Research Infrastructure (ICOS ERIC, https://www.icos-cp.eu/, last access: 3 October 2024) and the ICOS ETC funding from the Italian Ministry of Research. Mathias G\u00F6ckede was supported by the European Research Council (ERC) under the European Union\u2019s Horizon 2020 research and innovation program (grant agreement no. 951288, Q-Arctic). The DE-Geb site received funds within the ICOS Germany preparatory and implementation phase by the Federal Ministry of Education and Research and is supported by the Ministry of Digital and Traffic through ICOS station contributions as well as by the Ministry of Food and Agriculture covering operational costs. Giacomo A. Gerosa thanks the Catholic University of Brescia for continuous supporting the research station of Bosco Fontana (ICOS station IT-Bft). Ladislav \u0160igut acknowledges support by the Ministry of Education, Youth and Sports of CR within the CzeCOS program (grant number LM2023048) and the AdAgriF project (CZ.02.01.01/00/22_008/0004635). Gustau Camps-Valls, Markus Reichstein, Basil Kraft, and Gregory Duveiller acknowledge funding by the European Research Council (ERC) Synergy Grant \u201CUnderstanding and modeling the Earth System with Machine Learning (USMILE)\u201D under the European Union\u2019s Horizon 2020 research and innovation program (grant agreement no. 855187). Ankur Desai acknowledges the US Department of Energy American Network Management Project award to the ChEAS core site cluster (US-PFa, US-WCr, US-Syv, US-Los), Wisconsin Potato and Vegetable Growers Association, and WI Department of Natural Resources (US-CS\u2217), and NSF grant nos. 1822420, 2313772 (US-PFa). Marilyn Roland and Bert Gielen acknowledge the Research Foundation Flanders (FWO) for the support of ICOS research infrastructure in Flanders, Belgium. Dario Papale thanks the support of the ITINERIS \u2013 Italian Integrated Environmental Research Infrastructures System project (IR0000032) funded by NextGenerationEU Mission 4.2.3.1. Timo Vesala acknowledges ICOS-Finland (University of Helsinki) and Flagship funding (grant no. 337549). Torsten Sachs acknowledges that the DE-Zrk site relies on infrastructure of the Terrestrial Environmental Observatories Network (TERENO) supported by a Helmholtz Young Investigators Grant (VH-NG-821). Elise Pendall acknowledges Australian Terrestrial Ecosystem Research Network, as part of the National Cooperative Research Infrastructure System. Sara Knox was also supported by an NSERC Discovery Grant (RGPIN-2019-04199) and an Alliance Grant (ALLRP 555468-20). Hideki Kobayashi acknowledges ArC-SII no. JPMXD1420318865 (US-Prr). Stefan Metzger acknowledges the National Ecological Observatory Network, which is a program sponsored by the National Science Foundation and operated under cooperative agreement by Battelle. This material is based in part on work supported by the National Science Foundation through the NEON Program. Bernard Heinesch and Caroline Vincke acknowledge the Service Public de Wallonie (SPW-DGO6) for the support of ICOS research infrastructure in Wallonia, Belgium. This research has been supported by the National Science Foundation (grant nos. 2149988, 1932900, DEB LTREB 1354370, 2011257, DEB-0425328, DEB-0724514, DEB-0830997, 1936752, 1503912, 1107892, 1822420, and 2313772), the Deutsche Forschungsgemeinschaft (grant no. INST 186/1118-1 FUGG), the Nieders\u00E4chsische Ministerium f\u00FCr Wissenschaft und Kultur (grant no. ZN 3679), the Horizon 2020 (grant nos. 774124, 951288, 855187, 958927, 776810, 820852, and 776186), the Schweizerischer Nationalfonds zur F\u00F6rderung der Wissenschaftlichen Forschung (grant nos. 40FA40_154245, 146373, 407340_172433, 200021_197357, 100018L_200918, 20FI21_148992, 20FI20_173691, and 20FI20_198227), the ETH Z\u00FCrich Foundation (grant no. DONA), the Eidgen\u00F6ssische Technische Hochschule Z\u00FCrich (grant no. FEVER ETH-27 19-1), the Agencia Estatal de Investigaci\u00F3n (grant nos. PID2020-117825GB-C21 and PID2020-117825GB-C22), the Ministerio de Universidades (grant no. FPU19/01647), the Swedish National Space Agency (grant no. 2021-00144), the Australian Research Council (grant no. DE190101182), the Research Council of Finland (grant nos. N-PERM 341349 and 337549), the Ministerstvo \u0160kolstv\u00ED, Ml\u00E1de\u017Ee a T\u011Blov\u00FDchovy (grant no. LM2023048), the Ministry of Education, Culture, Sports, Science and Technology (grant no. JPMXD1420318865), the Helmholtz Association (grant no. VH-NG-821), the Natural Sciences and Engineering Research Council of Canada (grant nos. RGPIN-2019-04199 and ALLRP 555468-20), the European Space Agency (grant nos. Vad3e mecum, 4000134598/21/I-NB, and 4000123553/18/I-NB), the Horizon Europe Framework Programme, Horizon Europe Excellent Science (grant nos. 101059548, 20FI20_173691, 101079192, and 101056921), and the Vetenskapsr\u00E5det (grant no. 2021-00644).
Publisher Copyright:
© Author(s) 2024.