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Frédéric Chevallier - One of the best experts on this subject based on the ideXlab platform.
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Gridded fossil CO 2 emissions and related O 2 combustion consistent with national inventories 1959–2018
Scientific data, 2021Co-Authors: Matthew W. Jones, Prabir K. Patra, Philippe Ciais, Frédéric Chevallier, Robbie M. Andrew, Glen P. Peters, Greet Janssens-maenhout, Anthony J. De-gol, Corinne Le QuéréAbstract:Quantification of CO2 fluxes at the Earth's surface is required to evaluate the causes and drivers of observed increases in Atmospheric CO2 concentrations. Atmospheric Inversion models disaggregate observed variations in Atmospheric CO2 concentration to variability in CO2 emissions and sinks. They require prior constraints fossil CO2 emissions. Here we describe GCP-GridFED (version 2019.1), a gridded fossil emissions dataset that is consistent with the national CO2 emissions reported by the Global Carbon Project (GCP). GCP-GridFEDv2019.1 provides monthly fossil CO2 emissions estimates for the period 1959-2018 at a spatial resolution of 0.1°. Estimates are provided separately for oil, coal and natural gas, for mixed international bunker fuels, and for the calcination of limestone during cement production. GCP-GridFED also includes gridded estimates of O2 uptake based on oxidative ratios for oil, coal and natural gas. It will be updated annually and made available for Atmospheric Inversions contributing to GCP global carbon budget assessments, thus aligning the prior constraints on top-down fossil CO2 emissions with the bottom-up estimates compiled by the GCP.
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Gridded fossil CO_2 emissions and related O_2 combustion consistent with national inventories 1959–2018
Scientific Data, 2021Co-Authors: Matthew W. Jones, Prabir K. Patra, Philippe Ciais, Frédéric Chevallier, Robbie M. Andrew, Glen P. Peters, Greet Janssens-maenhout, Anthony J. De-gol, Corinne Le quéréAbstract:Measurement(s) carbon dioxide emission • oxygen combustion Technology Type(s) digital curation • computational modeling technique Factor Type(s) annual and monthly fossil carbon dioxide emissions estimates • annual and monthly oxygen combustion estimates Sample Characteristic - Environment climate system Sample Characteristic - Location global Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.13333643 Quantification of CO_2 fluxes at the Earth’s surface is required to evaluate the causes and drivers of observed increases in Atmospheric CO_2 concentrations. Atmospheric Inversion models disaggregate observed variations in Atmospheric CO_2 concentration to variability in CO_2 emissions and sinks. They require prior constraints fossil CO_2 emissions. Here we describe GCP-GridFED (version 2019.1), a gridded fossil emissions dataset that is consistent with the national CO_2 emissions reported by the Global Carbon Project (GCP). GCP-GridFEDv2019.1 provides monthly fossil CO_2 emissions estimates for the period 1959–2018 at a spatial resolution of 0.1°. Estimates are provided separately for oil, coal and natural gas, for mixed international bunker fuels, and for the calcination of limestone during cement production. GCP-GridFED also includes gridded estimates of O_2 uptake based on oxidative ratios for oil, coal and natural gas. It will be updated annually and made available for Atmospheric Inversions contributing to GCP global carbon budget assessments, thus aligning the prior constraints on top-down fossil CO_2 emissions with the bottom-up estimates compiled by the GCP.
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The Community Inversion Framework v1.0: a unified system for Atmospheric Inversion studies
2020Co-Authors: Antoine Berchet, Rona Thompson, Grégoire Broquet, Frédéric Chevallier, Espen Sollum, Isabelle Pison, Joël Thanwerdas, Tuula Aalto, Peter Bergamaschi, Dominik BrunnerAbstract:Abstract. Atmospheric Inversion approaches are expected to play a critical role in future observation-based monitoring systems for surface greenhouse gas (GHG) fluxes. In the past decade, the research community has developed various Inversion softwares, mainly using variational or ensemble Bayesian optimization methods, with various assumptions on uncertainty structures and prior information and with various Atmospheric chemistry-transport models. Each of them can assimilate some or all of the available observation streams for its domain area of interest: flask samples, in-situ measurements or satellite observations. Although referenced in peer-reviewed publications and usually accessible across the research community, most systems are not at the level of transparency, flexibility and accessibility needed to provide the scientific community and policy makers with a comprehensive and robust view of the uncertainties associated with the inverse estimation of GHG fluxes. Furthermore, their development, usually carried out by individual research institutes, may in the future not keep pace with the increasing scientific needs and technical possibilities. We present here a Community Inversion Framework (CIF) to help rationalize development efforts and leverage the strengths of individual Inversion systems into a comprehensive framework. The CIF is primarily a programming protocol to allow various Inversion bricks to be exchanged among researchers. In practice, the ensemble of bricks makes a flexible, transparent and open-source python-based tool to estimate the fluxes of various GHGs both at global and regional scales. It will allow running different Atmospheric transport models, different observation streams and different data assimilation approaches. This adaptability will allow a comprehensively assessment of uncertainty in a fully consistent framework. We present here the main structure and functionalities of the system, and demonstrate how it operates in a simple academic case.
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State of the science in reconciling top-down and bottom-up approaches for terrestrial CO2 budget
Global change biology, 2019Co-Authors: Masayuki Kondo, Prabir K. Patra, Philippe Ciais, Frédéric Chevallier, B. Poulter, Stephen Sitch, Pierre Friedlingstein, Josep G. Canadell, Ana Bastos, Ronny LauerwaldAbstract:Robust estimates of CO2 budget, CO2 exchanged between the atmosphere and terrestrial biosphere, are necessary to better understand the role of the terrestrial biosphere in mitigating anthropogenic CO2 emissions. Over the past decade, this field of research has advanced through understanding of the differences and similarities of two fundamentally different approaches: "top-down" Atmospheric Inversions and "bottom-up" biosphere models. Since the first studies were undertaken, these approaches have shown an increasing level of agreement, but disagreements in some regions still persist, in part because they do not estimate the same quantity of atmosphere-biosphere CO2 exchange. Here, we conducted a thorough comparison of CO2 budgets at multiple scales and from multiple methods to assess the current state of the science in estimating CO2 budgets. Our set of Atmospheric Inversions and biosphere models, which were adjusted for a consistent flux definition, showed a high level of agreement for global and hemispheric CO2 budgets in the 2000s. Regionally, improved agreement in CO2 budgets was notable for North America and Southeast Asia. However, large gaps between the two methods remained in East Asia and South America. In other regions, Europe, boreal Asia, Africa, South Asia, and Oceania, it was difficult to determine whether those regions act as a net sink or source because of the large spread in estimates from Atmospheric Inversions. These results highlight two research directions to improve the robustness of CO2 budgets: (a) to increase representation of processes in biosphere models that could contribute to fill the budget gaps, such as forest regrowth and forest degradation; and (b) to reduce sink-source compensation between regions (dipoles) in Atmospheric Inversion so that their estimates become more comparable. Advancements on both research areas will increase the level of agreement between the top-down and bottom-up approaches and yield more robust knowledge of regional CO2 budgets.
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The 2015-2016 carbon cycle as seen from OCO-2 and the global in situ network
Atmospheric Chemistry and Physics, 2019Co-Authors: Sean Crowell, Junjie Liu, Frédéric Chevallier, Feng Deng, Sourish Basu, David Baker, Andrew Schuh, Liang Feng, Andrew Jacobson, Kathryn MckainAbstract:The Orbiting Carbon Observatory-2 has been on orbit since 2014, and its global coverage holds the potential to reveal new information about the carbon cycle through the use of top-down Atmospheric Inversion methods combined with column average CO 2 retrievals. We employ a large ensemble of Atmospheric Inversions utilizing different transport models, data assimilation techniques, and prior flux distributions in order to quantify the satellite-informed fluxes from OCO-2 Version 7r land observations and their uncertainties at continental scales. Additionally, we use in situ measurements to provide a baseline against which to compare the satellite-constrained results. We find that within the ensemble spread, in situ observations, and satellite retrievals constrain a similar global total carbon sink of 3.7 ± 0.5 PgC yr −1 , and 1.5±0.6 PgC yr −1 for global land, for the 2015-2016 annual mean. This agreement breaks down in smaller regions, and we discuss the differences between the experiments. Of particular interest is the difference between the different assimilation constraints in the tropics, with the largest differences occurring in tropical Africa, which could be an indication of the global perturbation from the 2015-2016 El Niño. Evaluation of posterior concentrations using TCCON and aircraft observations gives some limited insight into the quality of the different assimilation constraints, but the lack of such data in the tropics inhibits our ability to make strong conclusions there. Copyright statement. The works published in this journal are distributed under the Creative Commons Attribution 4.0 License. This license does not affect the Crown copyright work, which is re-usable under the Open Government Licence (OGL). The Creative Commons Attribution 4.0 License and the OGL are interoperable and do not conflict with, reduce or limit each other. Published by Copernicus Publications on behalf of the European Geosciences Union. 9798 S. Crowell et al.: The 2015-2016 carbon cycle as seen from OCO-2 and the global in situ network
Feng Deng - One of the best experts on this subject based on the ideXlab platform.
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The 2015-2016 carbon cycle as seen from OCO-2 and the global in situ network
Atmospheric Chemistry and Physics, 2019Co-Authors: Sean Crowell, Junjie Liu, Frédéric Chevallier, Feng Deng, Sourish Basu, David Baker, Andrew Schuh, Liang Feng, Andrew Jacobson, Kathryn MckainAbstract:The Orbiting Carbon Observatory-2 has been on orbit since 2014, and its global coverage holds the potential to reveal new information about the carbon cycle through the use of top-down Atmospheric Inversion methods combined with column average CO 2 retrievals. We employ a large ensemble of Atmospheric Inversions utilizing different transport models, data assimilation techniques, and prior flux distributions in order to quantify the satellite-informed fluxes from OCO-2 Version 7r land observations and their uncertainties at continental scales. Additionally, we use in situ measurements to provide a baseline against which to compare the satellite-constrained results. We find that within the ensemble spread, in situ observations, and satellite retrievals constrain a similar global total carbon sink of 3.7 ± 0.5 PgC yr −1 , and 1.5±0.6 PgC yr −1 for global land, for the 2015-2016 annual mean. This agreement breaks down in smaller regions, and we discuss the differences between the experiments. Of particular interest is the difference between the different assimilation constraints in the tropics, with the largest differences occurring in tropical Africa, which could be an indication of the global perturbation from the 2015-2016 El Niño. Evaluation of posterior concentrations using TCCON and aircraft observations gives some limited insight into the quality of the different assimilation constraints, but the lack of such data in the tropics inhibits our ability to make strong conclusions there. Copyright statement. The works published in this journal are distributed under the Creative Commons Attribution 4.0 License. This license does not affect the Crown copyright work, which is re-usable under the Open Government Licence (OGL). The Creative Commons Attribution 4.0 License and the OGL are interoperable and do not conflict with, reduce or limit each other. Published by Copernicus Publications on behalf of the European Geosciences Union. 9798 S. Crowell et al.: The 2015-2016 carbon cycle as seen from OCO-2 and the global in situ network
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The 2015–2016 carbon cycle as seen from OCO-2 and the global in situ network
Atmospheric Chemistry and Physics, 2019Co-Authors: Sean Crowell, Junjie Liu, Frédéric Chevallier, Feng Deng, Sourish Basu, A. E. Schuh, David Baker, Andrew R. Jacobson, Liang Feng, Kathryn MckainAbstract:Abstract. The Orbiting Carbon Observatory-2 has been on orbit since 2014, and its global coverage holds the potential to reveal new information about the carbon cycle through the use of top-down Atmospheric Inversion methods combined with column average CO2 retrievals. We employ a large ensemble of Atmospheric Inversions utilizing different transport models, data assimilation techniques, and prior flux distributions in order to quantify the satellite-informed fluxes from OCO-2 Version 7r land observations and their uncertainties at continental scales. Additionally, we use in situ measurements to provide a baseline against which to compare the satellite-constrained results. We find that within the ensemble spread, in situ observations, and satellite retrievals constrain a similar global total carbon sink of 3.7±0.5 PgC yr −1 , and 1.5±0.6 PgC yr −1 for global land, for the 2015–2016 annual mean. This agreement breaks down in smaller regions, and we discuss the differences between the experiments. Of particular interest is the difference between the different assimilation constraints in the tropics, with the largest differences occurring in tropical Africa, which could be an indication of the global perturbation from the 2015–2016 El Nino. Evaluation of posterior concentrations using TCCON and aircraft observations gives some limited insight into the quality of the different assimilation constraints, but the lack of such data in the tropics inhibits our ability to make strong conclusions there.
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The 2015–2016 Carbon Cycle As Seen from OCO-2 and the Global <i>In Situ</i> Network
2019Co-Authors: Sean Crowell, Junjie Liu, Frédéric Chevallier, Feng Deng, Sourish Basu, David Baker, Andrew Schuh, Andrew R. Jacobson, Liang Feng, Abhishek ChatterjeeAbstract:Abstract. The Orbiting Carbon Observatory-2 has been on orbit since 2014, and its global coverage holds the potential to reveal new information about the carbon cycle through the use of top-down Atmospheric Inversion methods combined with column average CO2 retrievals. We employ a large ensemble of Atmospheric Inversions utilizing different transport models, data assimilation techniques and prior flux distributions in order to quantify the satellite-informed fluxes from OCO-2 Version 7r land observations and their uncertainties at continental scales. Additionally, we use in situ measurements to provide a baseline against which to compare the satellite-constrained results. We find that within ensemble spread, in situ observations and satellite retrievals constrain a similar global total carbon sink of 3.7 ± 0.5 PgC, and 1.5 ± 0.6 PgC per year for global land, for the 2015–2016 annual mean. This agreement breaks down on smaller regions, and we discuss the differences between the experiments. Of particular interest is the difference between the different assimilation constraints in the tropics, with the largest differences occurring in tropical Africa, which could be an indication of the global perturbation from the 2015–2016 El Niño. Evaluation of posterior concentrations using TCCON and aircraft observations gives some limited insight into the quality of the different assimilation constraints, but the lack of such data in the tropics inhibits our ability to make strong conclusions there.
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Global Atmospheric CO<sub>2</sub> inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and Atmospheric growth rate
Biogeosciences, 2019Co-Authors: Benjamin Gaubert, Christian Rödenbeck, Frédéric Chevallier, Feng Deng, Wouter Peters, Sourish Basu, Britton Stephens, Eric Kort, Prabir Patra, Tazu SaekiAbstract:We have compared a suite of recent global CO 2 Atmospheric Inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO 2 concentration profiles against observations from the High-Performance
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Global Atmospheric CO 2 inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and Atmospheric growth rate
Biogeosciences, 2019Co-Authors: Benjamin Gaubert, Christian Rödenbeck, Prabir K. Patra, Frédéric Chevallier, Feng Deng, Wouter Peters, Sourish Basu, Britton B. Stephens, Eric A. Kort, Tazu SaekiAbstract:We have compared a suite of recent global CO 2 Atmospheric Inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO 2 concentration profiles against observations from the High-Performance
Wouter Peters - One of the best experts on this subject based on the ideXlab platform.
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Global Atmospheric CO 2 inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and Atmospheric growth rate
Biogeosciences, 2019Co-Authors: Benjamin Gaubert, Christian Rödenbeck, Prabir K. Patra, Frédéric Chevallier, Feng Deng, Wouter Peters, Sourish Basu, Britton B. Stephens, Eric A. Kort, Tazu SaekiAbstract:We have compared a suite of recent global CO 2 Atmospheric Inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO 2 concentration profiles against observations from the High-Performance
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Global Atmospheric CO<sub>2</sub> inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and Atmospheric growth rate
Biogeosciences, 2019Co-Authors: Benjamin Gaubert, Christian Rödenbeck, Frédéric Chevallier, Feng Deng, Wouter Peters, Sourish Basu, Britton Stephens, Eric Kort, Prabir Patra, Tazu SaekiAbstract:We have compared a suite of recent global CO 2 Atmospheric Inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO 2 concentration profiles against observations from the High-Performance
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The use of forest stand age information in an Atmospheric CO2 Inversion applied to North America
Biogeosciences, 2013Co-Authors: Feng Deng, Jing M. Chen, Wouter Peters, Yude Pan, Richard A. Birdsey, Kevin Mccullough, Jingfeng XiaoAbstract:Atmospheric Inversions have become an important tool in quantifying carbon dioxide (CO2) sinks and sources at a variety of spatiotemporal scales, but associated large uncertainties restrain the Inversion research community from reaching agreement on many important subjects. We enhanced an Atmospheric Inversion of the CO2 flux for North America by introducing spatially explicit information on forest stand age for US and Canada as an additional constraint, since forest carbon dynamics are closely related to time since disturbance. To use stand age information in the Inversion, we converted stand age into an age factor, and included the covariances between subcontinental regions in the Inversion based on the similarity of the age factors. Our Inversion results show that, considering age factors, regions with recently disturbed or old forests are often nudged towards carbon sources, while regions with middle-aged productive forests are shifted towards sinks. This conforms to stand age effects observed in flux networks. At the subcontinental level, our inverted carbon fluxes agree well with continuous estimates of net ecosystem carbon exchange (NEE) upscaled from eddy covariance flux data based on MODIS data. Inverted fluxes with the age constraint exhibit stronger correlation to these upscaled NEE estimates than those inverted without the age constraint. While the carbon flux at the continental and subcontinental scales is predominantly determined by Atmospheric CO2 observations, the age constraint is shown to have potential to improve the Inversion of the carbon flux distribution among subcontinental regions, especially for regions lacking Atmospheric CO2 observations.
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Nested Atmospheric Inversion for the terrestrial carbon sources and sinks in China
Biogeosciences, 2013Co-Authors: Fei Jiang, Jing M. Chen, A. Ding, H. W. Wang, Lingxi Zhou, L. X. Liu, Wouter PetersAbstract:Abstract. In this study, we establish a nested Atmospheric Inversion system with a focus on China using the Bayesian method. The global surface is separated into 43 regions based on the 22 TransCom large regions, with 13 small regions in China. Monthly CO2 concentrations from 130 GlobalView sites and 3 additional China sites are used in this system. The core component of this system is an Atmospheric transport matrix, which is created using the TM5 model with a horizontal resolution of 3° × 2°. The net carbon fluxes over the 43 global land and ocean regions are inverted for the period from 2002 to 2008. The inverted global terrestrial carbon sinks mainly occur in boreal Asia, South and Southeast Asia, eastern America and southern South America. Most China areas appear to be carbon sinks, with strongest carbon sinks located in Northeast China. From 2002 to 2008, the global terrestrial carbon sink has an increasing trend, with the lowest carbon sink in 2002. The inter-annual variation (IAV) of the land sinks shows remarkable correlation with the El Niño Southern Oscillation (ENSO). The terrestrial carbon sinks in China also show an increasing trend. However, the IAV in China is not the same as that of the globe. There is relatively stronger land sink in 2002, lowest sink in 2006, and strongest sink in 2007 in China. This IAV could be reasonably explained with the IAVs of temperature and precipitation in China. The mean global and China terrestrial carbon sinks over the period 2002–2008 are −3.20 ± 0.63 and −0.28 ± 0.18 PgC yr−1, respectively. Considering the carbon emissions in the form of reactive biogenic volatile organic compounds (BVOCs) and from the import of wood and food, we further estimate that China's land sink is about −0.31 PgC yr−1.
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Forest stand age information improves an inverse North American carbon flux estimate
2013Co-Authors: Feng Deng, Jing M. Chen, Wouter Peters, Yude Pan, Richard A. Birdsey, Kevin Mccullough, Jingfeng XiaoAbstract:Abstract. Atmospheric Inversions have become an important tool in quantifying carbon dioxide (CO2) sinks and sources at a variety of spatiotemporal scales, but associated large uncertainties restrain the Inversion research community from reaching agreements on many important subjects. We enhanced an Atmospheric Inversion of the CO2 flux for North America by introducing spatially-explicit information on forest stand age for US and Canada as an additional constraint, since forest carbon dynamics are closely related to time since disturbance. To use stand age information in the Inversion, we converted stand age into an age factor, and included the covariances between sub-continental regions in the Inversion based on the similarity of the age factors. Our Inversion results show that, considering age factors, regions with recently-disturbed or old forests are often nudged towards carbon sources, while regions with middle-aged productive forests are shifted towards sinks. This conforms to stand age effects observed in flux networks. At the sub-continental level, our inverted carbon fluxes agree well with continuous estimates of net ecosystem carbon exchange (NEE) upscaled from eddy covariance flux data (EC) based on MODIS data. Inverted fluxes with the age constraint exhibit stronger correlation to these upscaled NEE estimates than those inverted without the age constraint. While the carbon flux at the continental and sub-continental scales is predominantly determined by Atmospheric CO2 observations, the age constraint is shown to have potential to improve the Inversion of the carbon flux distribution among sub-continental regions, especially for regions lacking Atmospheric CO2 observations.
Jing M. Chen - One of the best experts on this subject based on the ideXlab platform.
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Atmospheric Inversion of surface carbon flux with consideration of the spatial distribution of US crop production and consumption
Biogeosciences, 2015Co-Authors: Jing M. Chen, Feng Deng, J. W. Fung, Tristram O. WestAbstract:Abstract. In order to improve quantification of the spatial distribution of carbon sinks and sources in the conterminous US, we conduct a nested global Atmospheric Inversion with detailed spatial information on crop production and consumption. County-level cropland net primary productivity, harvested biomass, soil carbon change, and human and livestock consumption data over the conterminous US are used for this purpose. Time-dependent Bayesian synthesis Inversions are conducted based on CO2 observations at 210 stations to infer CO2 fluxes globally at monthly time steps with a nested focus on 30 regions in North America. Prior land surface carbon fluxes are first generated using a biospheric model, and the Inversions are constrained using prior fluxes with and without adjustments for crop production and consumption over the 2002–2007 period. After these adjustments, the inverted regional carbon sink in the US Midwest increases from 0.25 ± 0.03 to 0.42 ± 0.13 Pg C yr−1, whereas the large sink in the US southeast forest region is weakened from 0.41 ± 0.12 to 0.29 ± 0.12 Pg C yr−1. These adjustments also reduce the inverted sink in the west region from 0.066 ± 0.04 to 0.040 ± 0.02 Pg C yr−1 because of high crop consumption and respiration by humans and livestock. The general pattern of sink increases in crop production areas and sink decreases (or source increases) in crop consumption areas highlights the importance of considering the lateral carbon transfer in crop products in Atmospheric inverse modeling, which provides a reliable Atmospheric perspective of the overall carbon balance at the continental scale but is unreliable for separating fluxes from different ecosystems.
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Optimizing photosynthetic and respiratory parameters based on the seasonal variation pattern in regional net ecosystem productivity obtained from Atmospheric Inversion
Science Bulletin, 2015Co-Authors: Zhuoqi Chen, Jing M. Chen, Xiaogu Zheng, Fei Jiang, Jun Qin, Shupeng Zhang, Wenping YuanAbstract:In this study, we explore the feasibility of optimizing ecosystem photosynthetic and respiratory parameters from the seasonal variation of the net carbon flux. An optimization scheme is proposed to estimate two key parameters (Vmax25 and Q10) by exploiting the seasonal variation in the net ecosystem carbon flux retrieved by an Atmospheric Inversion system. This scheme is implemented to estimate Vmax25 and Q10 of the boreal ecosystem productivity simulator (BEPS) to improve its NEP simulation in the boreal North American region. Then, in situ NEE observations at six eddy covariance sites are used to evaluate the NEE simulations from BEPS with initial and optimized parameters. The results show that the performance of the optimized BEPS is superior to that of the BEPS with the default parameter values. These results implicate that it is possible to optimize ecosystem model parameters by different sensitivities of Vmax25 and Q10 during growing and non-growing seasons through Atmospheric Inversion or data assimilation techniques.
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The use of forest stand age information in an Atmospheric CO2 Inversion applied to North America
Biogeosciences, 2013Co-Authors: Feng Deng, Jing M. Chen, Wouter Peters, Yude Pan, Richard A. Birdsey, Kevin Mccullough, Jingfeng XiaoAbstract:Atmospheric Inversions have become an important tool in quantifying carbon dioxide (CO2) sinks and sources at a variety of spatiotemporal scales, but associated large uncertainties restrain the Inversion research community from reaching agreement on many important subjects. We enhanced an Atmospheric Inversion of the CO2 flux for North America by introducing spatially explicit information on forest stand age for US and Canada as an additional constraint, since forest carbon dynamics are closely related to time since disturbance. To use stand age information in the Inversion, we converted stand age into an age factor, and included the covariances between subcontinental regions in the Inversion based on the similarity of the age factors. Our Inversion results show that, considering age factors, regions with recently disturbed or old forests are often nudged towards carbon sources, while regions with middle-aged productive forests are shifted towards sinks. This conforms to stand age effects observed in flux networks. At the subcontinental level, our inverted carbon fluxes agree well with continuous estimates of net ecosystem carbon exchange (NEE) upscaled from eddy covariance flux data based on MODIS data. Inverted fluxes with the age constraint exhibit stronger correlation to these upscaled NEE estimates than those inverted without the age constraint. While the carbon flux at the continental and subcontinental scales is predominantly determined by Atmospheric CO2 observations, the age constraint is shown to have potential to improve the Inversion of the carbon flux distribution among subcontinental regions, especially for regions lacking Atmospheric CO2 observations.
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Nested Atmospheric Inversion for the terrestrial carbon sources and sinks in China
Biogeosciences, 2013Co-Authors: Fei Jiang, Jing M. Chen, A. Ding, H. W. Wang, Lingxi Zhou, L. X. Liu, Wouter PetersAbstract:Abstract. In this study, we establish a nested Atmospheric Inversion system with a focus on China using the Bayesian method. The global surface is separated into 43 regions based on the 22 TransCom large regions, with 13 small regions in China. Monthly CO2 concentrations from 130 GlobalView sites and 3 additional China sites are used in this system. The core component of this system is an Atmospheric transport matrix, which is created using the TM5 model with a horizontal resolution of 3° × 2°. The net carbon fluxes over the 43 global land and ocean regions are inverted for the period from 2002 to 2008. The inverted global terrestrial carbon sinks mainly occur in boreal Asia, South and Southeast Asia, eastern America and southern South America. Most China areas appear to be carbon sinks, with strongest carbon sinks located in Northeast China. From 2002 to 2008, the global terrestrial carbon sink has an increasing trend, with the lowest carbon sink in 2002. The inter-annual variation (IAV) of the land sinks shows remarkable correlation with the El Niño Southern Oscillation (ENSO). The terrestrial carbon sinks in China also show an increasing trend. However, the IAV in China is not the same as that of the globe. There is relatively stronger land sink in 2002, lowest sink in 2006, and strongest sink in 2007 in China. This IAV could be reasonably explained with the IAVs of temperature and precipitation in China. The mean global and China terrestrial carbon sinks over the period 2002–2008 are −3.20 ± 0.63 and −0.28 ± 0.18 PgC yr−1, respectively. Considering the carbon emissions in the form of reactive biogenic volatile organic compounds (BVOCs) and from the import of wood and food, we further estimate that China's land sink is about −0.31 PgC yr−1.
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Forest stand age information improves an inverse North American carbon flux estimate
2013Co-Authors: Feng Deng, Jing M. Chen, Wouter Peters, Yude Pan, Richard A. Birdsey, Kevin Mccullough, Jingfeng XiaoAbstract:Abstract. Atmospheric Inversions have become an important tool in quantifying carbon dioxide (CO2) sinks and sources at a variety of spatiotemporal scales, but associated large uncertainties restrain the Inversion research community from reaching agreements on many important subjects. We enhanced an Atmospheric Inversion of the CO2 flux for North America by introducing spatially-explicit information on forest stand age for US and Canada as an additional constraint, since forest carbon dynamics are closely related to time since disturbance. To use stand age information in the Inversion, we converted stand age into an age factor, and included the covariances between sub-continental regions in the Inversion based on the similarity of the age factors. Our Inversion results show that, considering age factors, regions with recently-disturbed or old forests are often nudged towards carbon sources, while regions with middle-aged productive forests are shifted towards sinks. This conforms to stand age effects observed in flux networks. At the sub-continental level, our inverted carbon fluxes agree well with continuous estimates of net ecosystem carbon exchange (NEE) upscaled from eddy covariance flux data (EC) based on MODIS data. Inverted fluxes with the age constraint exhibit stronger correlation to these upscaled NEE estimates than those inverted without the age constraint. While the carbon flux at the continental and sub-continental scales is predominantly determined by Atmospheric CO2 observations, the age constraint is shown to have potential to improve the Inversion of the carbon flux distribution among sub-continental regions, especially for regions lacking Atmospheric CO2 observations.
Rona Thompson - One of the best experts on this subject based on the ideXlab platform.
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The Community Inversion Framework v1.0: a unified system for Atmospheric Inversion studies
2020Co-Authors: Antoine Berchet, Rona Thompson, Grégoire Broquet, Frédéric Chevallier, Espen Sollum, Isabelle Pison, Joël Thanwerdas, Tuula Aalto, Peter Bergamaschi, Dominik BrunnerAbstract:Abstract. Atmospheric Inversion approaches are expected to play a critical role in future observation-based monitoring systems for surface greenhouse gas (GHG) fluxes. In the past decade, the research community has developed various Inversion softwares, mainly using variational or ensemble Bayesian optimization methods, with various assumptions on uncertainty structures and prior information and with various Atmospheric chemistry-transport models. Each of them can assimilate some or all of the available observation streams for its domain area of interest: flask samples, in-situ measurements or satellite observations. Although referenced in peer-reviewed publications and usually accessible across the research community, most systems are not at the level of transparency, flexibility and accessibility needed to provide the scientific community and policy makers with a comprehensive and robust view of the uncertainties associated with the inverse estimation of GHG fluxes. Furthermore, their development, usually carried out by individual research institutes, may in the future not keep pace with the increasing scientific needs and technical possibilities. We present here a Community Inversion Framework (CIF) to help rationalize development efforts and leverage the strengths of individual Inversion systems into a comprehensive framework. The CIF is primarily a programming protocol to allow various Inversion bricks to be exchanged among researchers. In practice, the ensemble of bricks makes a flexible, transparent and open-source python-based tool to estimate the fluxes of various GHGs both at global and regional scales. It will allow running different Atmospheric transport models, different observation streams and different data assimilation approaches. This adaptability will allow a comprehensively assessment of uncertainty in a fully consistent framework. We present here the main structure and functionalities of the system, and demonstrate how it operates in a simple academic case.
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Acceleration of global N2O emissions seen from two decades of Atmospheric Inversion
Nature Climate Change, 2019Co-Authors: Rona Thompson, Luis Lassaletta, Prabir K. Patra, Chris Wilson, Kelley C. Wells, A. Gressent, E. N. Koffi, Martyn P. Chipperfield, Wilfried Winiwarter, Eric A. DavidsonAbstract:Nitrous oxide (N2O) is the third most important long-lived GHG and an important stratospheric ozone depleting substance. Agricultural practices and the use of N-fertilizers have greatly enhanced emissions of N2O. Here, we present estimates of N2O emissions determined from three global Atmospheric Inversion frameworks during the period 1998–2016. We find that global N2O emissions increased substantially from 2009 and at a faster rate than estimated by the IPCC emission factor approach. The regions of East Asia and South America made the largest contributions to the global increase. From the Inversion-based emissions, we estimate a global emission factor of 2.3 ± 0.6%, which is significantly larger than the IPCC Tier-1 default for combined direct and indirect emissions of 1.375%. The larger emission factor and accelerating emission increase found from the Inversions suggest that N2O emission may have a nonlinear response at global and regional scales with high levels of N-input. Estimates of N2O emissions are important given its role as a GHG. Atmospheric Inversions indicate emissions increased over the past decade at a rate 2.5 times that estimated using the IPCC default method, and the emissions response to N-input is larger than linear when N-input is high.
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Methane fluxes in the high northern latitudes for 2005–2013 estimated using a Bayesian Atmospheric Inversion
Atmospheric Chemistry and Physics, 2017Co-Authors: Rona Thompson, Tuula Aalto, Motoki Sasakawa, Toshinobu Machida, Doug Worthy, Jošt V. Lavrič, Cathrine Lund Myhre, Andreas StohlAbstract:Abstract. We present methane (CH4) flux estimates for 2005 to 2013 from a Bayesian Inversion focusing on the high northern latitudes (north of 50° N). Our Inversion is based on Atmospheric transport modelled by the Lagrangian particle dispersion model FLEXPART and CH4 observations from 17 in situ and five discrete flask-sampling sites distributed over northern North America and Eurasia. CH4 fluxes are determined at monthly temporal resolution and on a variable grid with maximum resolution of 1° × 1°. Our Inversion finds a CH4 source from the high northern latitudes of 82 to 84 Tg yr−1, constituting ∼ 15 % of the global total, compared to 64 to 68 Tg yr−1 (∼ 12 %) in the prior estimates. For northern North America, we estimate a mean source of 16.6 to 17.9 Tg yr−1, which is dominated by fluxes in the Hudson Bay Lowlands (HBL) and western Canada, specifically the province of Alberta. Our estimate for the HBL, of 2.7 to 3.4 Tg yr−1, is close to the prior estimate (which includes wetland fluxes from the land surface model, LPX-Bern) and to other independent Inversion estimates. However, our estimate for Alberta, of 5.0 to 5.8 Tg yr−1, is significantly higher than the prior (which also includes anthropogenic sources from the EDGAR-4.2FT2010 inventory). Since the fluxes from this region persist throughout the winter, this may signify that the anthropogenic emissions are underestimated. For northern Eurasia, we find a mean source of 52.2 to 55.5 Tg yr−1, with a strong contribution from fluxes in the Western Siberian Lowlands (WSL) for which we estimate a source of 19.3 to 19.9 Tg yr−1. Over the 9-year Inversion period, we find significant year-to-year variations in the fluxes, which in North America, and specifically in the HBL, appear to be driven at least in part by soil temperature, while in the WSL, the variability is more dependent on soil moisture. Moreover, we find significant positive trends in the CH4 fluxes in North America of 0.38 to 0.57 Tg yr−2, and northern Eurasia of 0.76 to 1.09 Tg yr−2. In North America, this could be due to an increase in soil temperature, while in North Eurasia, specifically Russia, the trend is likely due, at least in part, to an increase in anthropogenic sources.
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methane fluxes in the high northern latitudes for 2005 2013 estimated using a bayesian Atmospheric Inversion
Atmospheric Chemistry and Physics, 2016Co-Authors: Rona Thompson, Tuula Aalto, Motoki Sasakawa, Toshinobu Machida, Doug Worthy, Jošt V. Lavrič, Cathrine Lund Myhre, Andreas StohlAbstract:Abstract. We present methane (CH4) flux estimates for 2005 to 2013 from a Bayesian Inversion focusing on the high northern latitudes (north of 50° N). Our Inversion is based on Atmospheric transport modelled by the Lagrangian particle dispersion model FLEXPART and CH4 observations from 17 in situ and five discrete flask-sampling sites distributed over northern North America and Eurasia. CH4 fluxes are determined at monthly temporal resolution and on a variable grid with maximum resolution of 1° × 1°. Our Inversion finds a CH4 source from the high northern latitudes of 82 to 84 Tg yr−1, constituting ∼ 15 % of the global total, compared to 64 to 68 Tg yr−1 (∼ 12 %) in the prior estimates. For northern North America, we estimate a mean source of 16.6 to 17.9 Tg yr−1, which is dominated by fluxes in the Hudson Bay Lowlands (HBL) and western Canada, specifically the province of Alberta. Our estimate for the HBL, of 2.7 to 3.4 Tg yr−1, is close to the prior estimate (which includes wetland fluxes from the land surface model, LPX-Bern) and to other independent Inversion estimates. However, our estimate for Alberta, of 5.0 to 5.8 Tg yr−1, is significantly higher than the prior (which also includes anthropogenic sources from the EDGAR-4.2FT2010 inventory). Since the fluxes from this region persist throughout the winter, this may signify that the anthropogenic emissions are underestimated. For northern Eurasia, we find a mean source of 52.2 to 55.5 Tg yr−1, with a strong contribution from fluxes in the Western Siberian Lowlands (WSL) for which we estimate a source of 19.3 to 19.9 Tg yr−1. Over the 9-year Inversion period, we find significant year-to-year variations in the fluxes, which in North America, and specifically in the HBL, appear to be driven at least in part by soil temperature, while in the WSL, the variability is more dependent on soil moisture. Moreover, we find significant positive trends in the CH4 fluxes in North America of 0.38 to 0.57 Tg yr−2, and northern Eurasia of 0.76 to 1.09 Tg yr−2. In North America, this could be due to an increase in soil temperature, while in North Eurasia, specifically Russia, the trend is likely due, at least in part, to an increase in anthropogenic sources.
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TransCom N2O model inter-comparison, Part 2: Atmospheric Inversion estimates of N2O emissions
Atmospheric Chemistry and Physics, 2014Co-Authors: Rona Thompson, Prabir K. Patra, Frédéric Chevallier, Peter Bergamaschi, Kentaro Ishijima, Eri Saikawa, M. Corazza, Ute Karstens, Edward J. Dlugokencky, Ronald G. PrinnAbstract:Abstract. This study examines N2O emission estimates from five different Atmospheric Inversion frameworks based on chemistry transport models (CTMs). The five frameworks differ in the choice of CTM, meteorological data, prior uncertainties and Inversion method but use the same prior emissions and observation data set. The posterior modelled Atmospheric N2O mole fractions are compared to observations to assess the performance of the Inversions and to help diagnose problems in the modelled transport. Additionally, the mean emissions for 2006 to 2008 are compared in terms of the spatial distribution and seasonality. Overall, there is a good agreement among the Inversions for the mean global total emission, which ranges from 16.1 to 18.7 TgN yr−1 and is consistent with previous estimates. Ocean emissions represent between 31 and 38% of the global total compared to widely varying previous estimates of 24 to 38%. Emissions from the northern mid- to high latitudes are likely to be more important, with a consistent shift in emissions from the tropics and subtropics to the mid- to high latitudes in the Northern Hemisphere; the emission ratio for 0–30° N to 30–90° N ranges from 1.5 to 1.9 compared with 2.9 to 3.0 in previous estimates. The largest discrepancies across Inversions are seen for the regions of South and East Asia and for tropical and South America owing to the poor observational constraint for these areas and to considerable differences in the modelled transport, especially inter-hemispheric exchange rates and tropical convective mixing. Estimates of the seasonal cycle in N2O emissions are also sensitive to errors in modelled stratosphere-to-troposphere transport in the tropics and southern extratropics. Overall, the results show a convergence in the global and regional emissions compared to previous independent studies.