109 results on '"Broquet G"'
Search Results
2. Recent Changes in Global Photosynthesis and Terrestrial Ecosystem Respiration Constrained From Multiple Observations
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Li, W, Ciais, P, Wang, Y, Yin, Y, Peng, S, Zhu, Z, Bastos, A, Yue, C, Ballantyne, AP, Broquet, G, Canadell, JG, Cescatti, A, Chen, C, Cooper, L, Friedlingstein, P, Le Quéré, C, Myneni, RB, and Piao, S
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GPP trend ,Bayesian constraint ,terrestrial ecosystem respiration ,Meteorology & Atmospheric Sciences - Abstract
To assess global carbon cycle variability, we decompose the net land carbon sink into the sum of gross primary productivity (GPP), terrestrial ecosystem respiration (TER), and fire emissions and apply a Bayesian framework to constrain these fluxes between 1980 and 2014. The constrained GPP and TER fluxes show an increasing trend of only half of the prior trend simulated by models. From the optimization, we infer that TER increased in parallel with GPP from 1980 to 1990, but then stalled during the cooler periods, in 1990–1994 coincident with the Pinatubo eruption, and during the recent warming hiatus period. After each of these TER stalling periods, TER is found to increase faster than GPP, explaining a relative reduction of the net land sink. These results shed light on decadal variations of GPP and TER and suggest that they exhibit different responses to temperature anomalies over the last 35 years.
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- 2018
3. Five decades of northern land carbon uptake revealed by the interhemispheric CO2 gradient
- Author
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Ciais, P., Tan, J., Wang, X., Roedenbeck, C., Chevallier, F., Piao, S.-L., Moriarty, R., Broquet, G., Le Quéré, C., Canadell, J. G., Peng, S., Poulter, B., Liu, Z., and Tans, P.
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- 2019
- Full Text
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4. Iconic CO2 time series at risk
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Houweling, S, Badawy, B, Baker, DF, Basu, S, Belikov, D, Bergamaschi, P, Bousquet, P, Broquet, G, Butler, T, Canadell, JG, Chen, J, Chevallier, F, Ciais, P, Collatz, JG, Denning, S, Engelen, R, Enting, IG, Fischer, ML, Fraser, A, Gerbig, C, Gloor, M, Jacobson, AR, Jones, DBA, Heimann, M, Khalil, A, Kaminski, T, Kasibhatla, PS, Krakauer, NY, Krol, M, Maki, T, Maksyutov, S, Manning, A, Meesters, A, Miller, JB, Palmer, PI, Patra, P, Peters, W, Peylin, P, Poussi, Z, Prather, MJ, Randerson, JT, Röckmann, T, Rödenbeck, C, Sarmiento, JL, Schimel, DS, Scholze, M, Schuh, A, Suntharalingam, P, Takahashi, T, Turnbull, J, Yurganov, L, and Vermeulen, A
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- 2012
5. Analysis of the potential of near ground measurements of CO2 and CH4 in London, UK for the monitoring of city-scale emissions using an atmospheric transport model
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Boon, A., Broquet, G., Clifford, D. J., Chevallier, F., Butterfield, D. M., Pison, I., Ramonet, M., Paris, J. D., Ciais, P., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
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[SDU]Sciences of the Universe [physics] - Abstract
International audience; Carbon dioxide (CO2) and methane (CH4) mole fractions were measured at four near ground sites located in and around London during the summer of 2012 in view to investigate the potential of assimilating such measurements in an atmospheric inversion system for the monitoring of the CO2 and CH4 emissions in the London area. These data were analysed and compared with simulations using a modelling framework suited to building an inversion system: a 2 km horizontal resolution South of England configuration of the transport model CHIMERE driven by European Centre for Medium-Range Weather Forecasting (ECMWF) meteorological forcing, coupled to a 1 km horizontal resolution emission inventory (the UK National Atmospheric Emission Inventory). First comparisons reveal that local sources have a large impact on measurements and these local sources cannot be represented in the model at 2 km resolution. We evaluate methods to minimise some of the other critical sources of misfits between the observation data and the model simulation that overlap the signature of the errors in the emission inventory. These methods should make it easier to identify the corrections that should be applied to the inventory. Analysis is supported by observations from meteorological sites around the city and a three-week period of atmospheric mixing layer height estimations from lidar measurements. The difficulties of modelling the mixing layer depth and thus CO2 and CH4 concentrations during the night, morning and late afternoon led us to focus on the afternoon period for all further analyses. The misfits between observations and model simulations are high for both CO2 and CH4 (i.e., their root mean square (RMS) is between 8 and 12 parts per million (ppm) for CO2 and between 30 and 55 parts per billion (ppb) for CH4 at a given site). By analysing the gradients between the urban sites and a suburban or rural reference site, we are able to decrease the impact of uncertainties in the fluxes and transport outside the London area and in the model domain boundary conditions, and to better focus attention on the signature of London urban CO2 and CH4 emissions. This considerably improves the statistical agreement between the model and observations for CO2 (model-data RMS misfit of between 3 and 7 ppm) and to a lesser degree for CH4 (model-data RMS misfit of between 29 and 38 ppb). Between one of the urban sites and either reference site, selecting the gradients during periods wherein the reference site is upwind of the urban site further decreases the statistics of the misfits in general even though not systematically. In a final attempt to focus on the signature of the city anthropogenic emission in the mole fraction measurements, we use a theoretical ratio of gradients of CO to gradients of CO2 from fossil fuel emissions in the London area to diagnose observation based fossil fuel CO2 gradients, and compare them with the modelled ones. This estimate increases the consistency between the model and the measurements when considering one of the urban sites, but not when considering the other. While this study evaluates different approaches for increasing the consistency between the mesoscale model and the near ground data, and manages to decrease the random component of the analysed model data misfits to an extent that should not be prohibitive to extracting the signal from the London urban emissions, large biases remain in the final misfits. These biases are likely to be due to local emissions, to which the urban near ground sites are highly sensitive. This questions our current ability to exploit urban near ground data for the atmospheric inversion of city emissions based on models at spatial resolution coarser than 2 km.
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- 2023
6. Corrections to ocean surface forcing in the California Current System using 4D variational data assimilation
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Broquet, G., Moore, A.M., Arango, H.G., and Edwards, C.A.
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- 2011
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7. MRS-Screening-Test zur Registrierung der medikamentösen Beeinflussung des Muskeltonus
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Mennet, P., Broquet, G., Merz, N., Stratz, T., Müller, W., and Müller, W., editor
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- 1991
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8. Ganganalysen bei der generalisierten Tendomyopathie
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Broquet, G., Mennet, P., Merz, N., Stratz, T., Müller, W., and Müller, W., editor
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- 1991
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9. Application of 4D-Variational data assimilation to the California Current System
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Broquet, G., Edwards, C.A., Moore, A.M., Powell, B.S., Veneziani, M., and Doyle, J.D.
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- 2009
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10. Analysis of the Anthropogenic and Biogenic NOx Emissions Over 2008–2017: Assessment of the Trends in the 30 Most Populated Urban Areas in Europe
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Fortems‐Cheiney, A., primary, Broquet, G., additional, Pison, I., additional, Saunois, M., additional, Potier, E., additional, Berchet, A., additional, Dufour, G., additional, Siour, G., additional, Denier van der Gon, H., additional, Dellaert, S. N. C., additional, and Boersma, K. F., additional
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- 2021
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11. CarbonCGI road map to observe faint GHG source’s emissions with high resolution observing system
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Babu, Sachidananda R., Hélière, Arnaud, Kimura, Toshiyoshi, Siméoni, D., Graziosi, F., Broquet, G., Kumar, P., Ciais, P., Vergely, J. L., Ferron, S., Khodnevych, V., Carlavan, M., Chétrite, B., Tetaz, N., Delzenne, C., Guercio, N., Boesch, H., Vogel, L., Mariani, F., Windpassinger, R., and Sierk, B.
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- 2022
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12. Percepción
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Munar Roca, E., primary, Rosselló Mir, J., additional, Cela-Conde, C.J., additional, Marty Broquet, G., additional, and Nadal Roberts, M., additional
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- 2008
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13. Biofuel burning and human respiration bias on satellite estimates of fossil fuel CO2 emissions
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Ciais, P, primary, Wang, Y, additional, Andrew, R, additional, Bréon, F M, additional, Chevallier, F, additional, Broquet, G, additional, Nabuurs, G J, additional, Peters, G, additional, McGrath, M, additional, Meng, W, additional, Zheng, B, additional, and Tao, S, additional
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- 2020
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14. Biofuel burning and human respiration bias on satellite estimates of fossil fuel CO2 emissions.
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Ciais, P, Wang, Y, Andrew, R, Bréon, F M, Chevallier, F, Broquet, G, Nabuurs, G J, Peters, G, McGrath, M, Meng, W, Zheng, B, and Tao, S
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- 2020
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15. Assessing the role of megacities on atmospheric CO2: results for Paris from the CO2- MegaParis project, France
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Xueref-Remy, Irène, Dieudonné, Elsa, Vuillemin, C., Lopez, M., Lac, C., Delmotte, M., Ravetta, François, Perrussel, O., Breon, Francois-Marie, Broquet, G., Schmidt, M., Chevallier, F., Masson, V., Ciais, P., Ramonet, M., Ampe, C., Ammoura, L., Gros, V., Baudic, A., Bonsang, B., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), ICOS-RAMCES (ICOS-RAMCES), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Institut für Umweltphysik [Heidelberg], Universität Heidelberg [Heidelberg], ICOS-ATC (ICOS-ATC), Chimie Atmosphérique Expérimentale (CAE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Universität Heidelberg [Heidelberg] = Heidelberg University
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[SDE]Environmental Sciences - Abstract
International audience; On average, atmospheric CO2 increases in the atmosphere at a rate of about 2 parts per million (ppm) per year, due to the accumulation of about half of the anthropogenic CO2 emissions in the atmosphere (mostly from the combustion of fossil fuels), while the other half is being re-absorbed by the ocean and the continental biosphere. today, more than 70% of global fossil-fuel CO2 emissions come from punctual sources such as megacities. paris is the third megacity in europe and it emits about 15% of the total French emissions, while it covers only less than 2% of the national territory. Currently, most of the estimates of urban CO2 emissions are given by bottom-up CO2 emissions inventories, which rely on activity proxies and benchmarked emission factors. the associated uncertainties can be as high as several tenths of percents, especially when it comes to discriminate the CO2 urban emissions by emission sectors. therefore, there is an urgent need for developing new methods to better Monitoring, reporting and Veryfying (MrV) CO2 emissions from megacities, dedicated to provide robust results to policy makers for taking efficient decisions and actions in matter of controling CO2 anthropogenic emissions and mitigating climate change. since 2009, the CO2-Megaparis project aims to quantify CO2 emissions from paris using top-down approaches based on a synergy between atmospheric observations and modeling. For the first time, a mini-network of 3 greenhouse gases (GHG) monitoring stations was developed by lsCe in paris agglomeration within the infrastructure of the regional air quality monitoring agency, airpariF, completing 2 other GHG stations from the iCOs european greenhouse monitoring network. One of our urban station was located on top of the eiffel tower above paris megacity. the analysis of one year of data showed that paris CO2 emissions lead to a mean increase of the atmospheric CO2 concentration in the mid-afternoon of 2 to 3 ppm, and is strongly season, windspeed and wind direction dependent: the CO2 urban plume is characterized by a very large spatio-temporal variability and can reach about 60 ppm at low windspeeds on top of the eiffel tower. in addition, analysis of correlations between CO2, CO and 14C02 were carried out from field measurements and allowed an independent assessment of the inventories emission sectors. Furthermore, direct modeling of CO2 at a very fine resolution (2x2 km2, 1h) was performed and matched well with the observations. last but not least, inverse modeling efforts at the same resolution allowed a significant improvment of the regional inventory from airparif. Finally, a campaign conducted during springtime and based on lidar facilities revealed that due to the effect of the urban heat island, the boundary layer height (that can be seen on the first degree as the man dilution factor of CO2 emissions in the atmosphere), is 10 to 40% time higher in Paris than in surrounding rural areas: this is an important result that supports the implementation of urban canopy models in future fine scale urban CO2 modeling framework. a synthesis of the different results will be presented, as well as an attempt of defining the strengths and weaknesses of the atmospheric approach to quantify urban CO2 emissions. Contributions from sister studies (MultiCO2 - ipsl, le CO2 parisien - Ville de paris 2030, CarboCount-City - KiC Climat...) will also be mentionned.
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- 2015
16. On the potential of the ICOS atmospheric CO2 measurement network for estimating the biogenic CO2 budget of Europe
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Kadygrov, N., Broquet, G., Chevallier, F., Rivier, L., Gerbig, C., Ciais, P., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Department of Earth and Planetary Sciences [Cambridge, USA] (EPS), Harvard University [Cambridge], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Harvard University
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lcsh:Chemistry ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,lcsh:QD1-999 ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,lcsh:Physics ,lcsh:QC1-999 - Abstract
We present a performance assessment of the European Integrated Carbon Observing System (ICOS) atmospheric network for constraining European biogenic CO2 fluxes (hereafter net ecosystem exchange, NEE). The performance of the network is assessed in terms of uncertainty in the fluxes, using a state-of-the-art mesoscale variational atmospheric inversion system assimilating hourly averages of atmospheric data to solve for NEE at 6 h and 0.5° resolution. The performance of the ICOS atmospheric network is also assessed in terms of uncertainty reduction compared to typical uncertainties in the flux estimates from ecosystem models, which are used as prior information by the inversion. The uncertainty in inverted fluxes is computed for two typical periods representative of northern summer and winter conditions in July and in December 2007, respectively. These computations are based on a observing system simulation experiment (OSSE) framework. We analyzed the uncertainty in a 2-week-mean NEE as a function of the spatial scale with a focus on the model native grid scale (0.5°), the country scale and the European scale (including western Russia and Turkey). Several network configurations, going from 23 to 66 sites, and different configurations of the prior uncertainties and atmospheric model transport errors are tested in order to assess and compare the improvements that can be expected in the future from the extension of the network, from improved prior information or transport models. Assimilating data from 23 sites (a network comparable to present-day capability) with errors estimated from the present prior information and transport models, the uncertainty reduction on a 2-week-mean NEE should range between 20 and 50 % for 0.5° resolution grid cells in the best sampled area encompassing eastern France and western Germany. At the European scale, the prior uncertainty in a 2-week-mean NEE is reduced by 50 % (66 %), down to ~ 43 Tg C month−1 (26 Tg C month−1) in July (December). Using a larger network of 66 stations, the prior uncertainty of NEE is reduced by the inversion by 64 % (down to ~ 33 Tg C month−1) in July and by 79 % (down to ~ 15 Tg C month−1) in December. When the results are integrated over the well-observed western European domain, the uncertainty reduction shows no seasonal variability. The effect of decreasing the correlation length of the prior uncertainty, or of reducing the transport model errors compared to their present configuration (when conducting real-data inversion cases) can be larger than that of the extension of the measurement network in areas where the 23 station observation network is the densest. We show that with a configuration of the ICOS atmospheric network containing 66 sites that can be expected on the long-term, the uncertainties in a 2-week-mean NEE will be reduced by up to 50–80 % for countries like Finland, Germany, France and Spain, which could significantly improvement (and at least a high complementarity to) our knowledge of NEE derived from biomass and soil carbon inventories at multi-annual scales.
- Published
- 2015
17. On the potential of ICOS atmospheric CO2 measurement network for estimating the biogenic CO2 budget of Europe
- Author
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Kadygrov, N., Broquet, G., Chevallier, F., Rivier, L., Gerbig, C., and Ciais, P.
- Abstract
We present a performance assessment of the European Integrated Carbon Observing System (ICOS) atmospheric network for constraining European biogenic CO2 fluxes (hereafter net ecosystem exchange, NEE). The performance of the network is assessed in terms of uncertainty in the fluxes, using a state-of-the-art mesoscale variational atmospheric inversion system assimilating hourly averages of atmospheric data to solve for NEE at 6 h and 0.5° resolution. The performance of the ICOS atmospheric network is also assessed in terms of uncertainty reduction compared to typical uncertainties in the flux estimates from ecosystem models, which are used as prior information by the inversion. The uncertainty in inverted fluxes is computed for two typical periods representative of northern summer and winter conditions in July and in December 2007, respectively. These computations are based on a observing system simulation experiment (OSSE) framework. We analyzed the uncertainty in a 2-week-mean NEE as a function of the spatial scale with a focus on the model native grid scale (0.5°), the country scale and the European scale (including western Russia and Turkey). Several network configurations, going from 23 to 66 sites, and different configurations of the prior uncertainties and atmospheric model transport errors are tested in order to assess and compare the improvements that can be expected in the future from the extension of the network, from improved prior information or transport models. Assimilating data from 23 sites (a network comparable to present-day capability) with errors estimated from the present prior information and transport models, the uncertainty reduction on a 2-week-mean NEE should range between 20 and 50 % for 0.5° resolution grid cells in the best sampled area encompassing eastern France and western Germany. At the European scale, the prior uncertainty in a 2-week-mean NEE is reduced by 50 % (66 %), down to ~ 43 Tg C month−1 (26 Tg C month−1) in July (December). Using a larger network of 66 stations, the prior uncertainty of NEE is reduced by the inversion by 64 % (down to ~ 33 Tg C month−1) in July and by 79 % (down to ~ 15 Tg C month−1) in December. When the results are integrated over the well-observed western European domain, the uncertainty reduction shows no seasonal variability. The effect of decreasing the correlation length of the prior uncertainty, or of reducing the transport model errors compared to their present configuration (when conducting real-data inversion cases) can be larger than that of the extension of the measurement network in areas where the 23 station observation network is the densest. We show that with a configuration of the ICOS atmospheric network containing 66 sites that can be expected on the long-term, the uncertainties in a 2-week-mean NEE will be reduced by up to 50–80 % for countries like Finland, Germany, France and Spain, which could significantly improvement (and at least a high complementarity to) our knowledge of NEE derived from biomass and soil carbon inventories at multi-annual scales.
- Published
- 2015
18. Five decades of northern land carbon uptake revealed by the interhemispheric CO2 gradient.
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Ciais, P., Tan, J., Wang, X., Roedenbeck, C., Chevallier, F., Piao, S.-L., Moriarty, R., Broquet, G., Le Quéré, C., Canadell, J. G., Peng, S., Poulter, B., Liu, Z., and Tans, P.
- Abstract
The global land and ocean carbon sinks have increased proportionally with increasing carbon dioxide emissions during the past decades1. It is thought that Northern Hemisphere lands make a dominant contribution to the global land carbon sink2–7; however, the long-term trend of the northern land sink remains uncertain. Here, using measurements of the interhemispheric gradient of atmospheric carbon dioxide from 1958 to 2016, we show that the northern land sink remained stable between the 1960s and the late 1980s, then increased by 0.5 ± 0.4 petagrams of carbon per year during the 1990s and by 0.6 ± 0.5 petagrams of carbon per year during the 2000s. The increase of the northern land sink in the 1990s accounts for 65% of the increase in the global land carbon flux during that period. The subsequent increase in the 2000s is larger than the increase in the global land carbon flux, suggesting a coincident decrease of carbon uptake in the Southern Hemisphere. Comparison of our findings with the simulations of an ensemble of terrestrial carbon models5,8 over the same period suggests that the decadal change in the northern land sink between the 1960s and the 1990s can be explained by a combination of increasing concentrations of atmospheric carbon dioxide, climate variability and changes in land cover. However, the increase during the 2000s is underestimated by all models, which suggests the need for improved consideration of changes in drivers such as nitrogen deposition, diffuse light and land-use change. Overall, our findings underscore the importance of Northern Hemispheric land as a carbon sink. Measurements of the interhemispheric gradient of atmospheric carbon dioxide show that the Northern Hemisphere carbon land sink remained stable between the 1960s and the late 1980s, then increased during the 1990s and 2000s. [ABSTRACT FROM AUTHOR]
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- 2019
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19. Constraining CO2 emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia
- Author
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Konovalov, I. B., Berezin, E. V., Ciais, P., Broquet, G., Beekmann, Matthias, Hadji-Lazaro, Juliette, Clerbaux, Cathy, Andreae, M. O., Kaiser, J. W., Schulze, E.-D., Institute of Applied Physics of RAS, Russian Academy of Sciences [Moscow] (RAS), Lobachevsky State University [Nizhni Novgorod], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Chemie (MPIC), Max-Planck-Gesellschaft, European Centre for Medium-Range Weather Forecasts (ECMWF), King‘s College London, Max-Planck-Institut für Biogeochemie (MPI-BGC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
lcsh:Chemistry ,[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] ,lcsh:QD1-999 ,[SDE]Environmental Sciences ,lcsh:Physics ,lcsh:QC1-999 - Abstract
A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. CO2 emissions are assessed by means of an emission model assuming a direct relationship between the biomass burning rate (BBR) and the fire radiative power (FRP) derived from MODIS measurements. The key features of the method are (1) estimating the FRP-to-BBR conversion factors (α) for different vegetative land cover types by assimilating the satellite observations of co-emitted species into the CTM, (2) optimal combination of the estimates of α derived independently from satellite observations of different species (CO and aerosol in this study), and (3) estimation of the diurnal cycle of the fire emissions directly from the FRP measurements. Values of α for forest and grassland fires in Siberia and their uncertainties are estimated using the Infrared Atmospheric Sounding Interferometer (IASI) carbon monoxide (CO) retrievals and MODIS aerosol optical depth (AOD) measurements combined with outputs from the CHIMERE mesoscale chemistry-transport model. The constrained CO emissions are validated through comparison of the respective simulations with independent data of ground-based CO measurements at the ZOTTO site. Using our optimal regional-scale estimates of the conversion factors (which are found to be in agreement with earlier published estimates obtained from local measurements of experimental fires), the total CO2 emissions from wildfires in Siberia in 2012 are estimated to be in the range from 280 to 550 Tg C, with the optimal (maximum likelihood) value of 392 Tg C. Sensitivity test cases featuring different assumptions regarding the injection height and diurnal variations of emissions indicate that the derived estimates of the total CO2 emissions in Siberia are robust with respect to the modeling options (the different estimates vary within less than 15% of their magnitude). The CO2 emission estimates obtained for several years are compared with independent estimates provided by the GFED3.1 and GFASv1.0 global emission inventories. It is found that our "top-down" estimates for the total annual biomass burning CO2 emissions in the period from 2007 to 2011 in Siberia are by factors of 2.5 and 1.8 larger than the respective bottom-up estimates; these discrepancies cannot be fully explained by uncertainties in our estimates. There are also considerable differences in the spatial distribution of the different emission estimates; some of those differences have a systematic character and require further analysis.
- Published
- 2014
20. An objective prior error quantification for regional atmospheric inverse applications
- Author
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Kountouris, P., primary, Gerbig, C., additional, Totsche, K.-U., additional, Dolman, A. J., additional, Meesters, A. G. C. A., additional, Broquet, G., additional, Maignan, F., additional, Gioli, B., additional, Montagnani, L., additional, and Helfter, C., additional
- Published
- 2015
- Full Text
- View/download PDF
21. Decadal trends in global CO emissions as seen by MOPITT
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Yin, Y., primary, Chevallier, F., additional, Ciais, P., additional, Broquet, G., additional, Fortems-Cheiney, A., additional, Pison, I., additional, and Saunois, M., additional
- Published
- 2015
- Full Text
- View/download PDF
22. Analysis of the potential of near ground measurements of CO<sub>2</sub> and CH<sub>4</sub> in London, UK for the monitoring of city-scale emissions using an atmospheric transport model
- Author
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Boon, A., primary, Broquet, G., additional, Clifford, D. J., additional, Chevallier, F., additional, Butterfield, D. M., additional, Pison, I., additional, Ramonet, M., additional, Paris, J. D., additional, and Ciais, P., additional
- Published
- 2015
- Full Text
- View/download PDF
23. Atmospheric inversion for cost effective quantification of city CO2 emissions
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Wu, L., primary, Broquet, G., additional, Ciais, P., additional, Bellassen, V., additional, Vogel, F., additional, Chevallier, F., additional, Xueref-Remy, I., additional, and Wang, Y., additional
- Published
- 2015
- Full Text
- View/download PDF
24. Supplementary material to "Atmospheric inversion for cost effective quantification of city CO<sub>2</sub> emissions"
- Author
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Wu, L., primary, Broquet, G., additional, Ciais, P., additional, Bellassen, V., additional, Vogel, F., additional, Chevallier, F., additional, Xueref-Remy, I., additional, and Wang, Y., additional
- Published
- 2015
- Full Text
- View/download PDF
25. Regional inversion of CO2 ecosystem fluxes from atmospheric measurements: reliability of the uncertainty estimates
- Author
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Broquet, G., Chevallier, F., Breon, F., Kadygrov, N., Alemanno, M., Apadula, F., Hammer, S., Haszpra, L., Meinhardt, F., Morgui, J., Necki, J., Piacentino, S., Ramonet, M., Schmidt, M., Thompson, R., Vermeulen, A., Yver, C., Ciais, P., Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut für Umweltphysik [Heidelberg], Universität Heidelberg [Heidelberg], Hungarian Meteorological Service (OMSz), German Federal Environmental Agency / Umweltbundesamt (UBA), Institut Català de Ciències del Clima, AGH University of Science and Technology [Krakow, PL] (AGH UST), Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile (ENEA), ICOS-RAMCES (ICOS-RAMCES), Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft, Energy Research Centre of the Netherlands (ECN), ICOS-ATC (ICOS-ATC), The publication of this articleis financed by CNRS-INSU., Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg] = Heidelberg University, Hungarian Meteorological Service (OMSZ), and Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA)
- Subjects
lcsh:Chemistry ,[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] ,lcsh:QD1-999 ,Physics::Atmospheric and Oceanic Physics ,lcsh:Physics ,lcsh:QC1-999 - Abstract
The Bayesian framework of CO2 flux inversions permits estimates of the retrieved flux uncertainties. Here, the reliability of these theoretical estimates is studied through a comparison against the misfits between the inverted fluxes and independent measurements of the CO2 Net Ecosystem Exchange (NEE) made by the eddy covariance technique at local (few hectares) scale. Regional inversions at 0.5° resolution are applied for the western European domain where ~ 50 eddy covariance sites are operated. These inversions are conducted for the period 2002–2007. They use a mesoscale atmospheric transport model, a prior estimate of the NEE from a terrestrial ecosystem model and rely on the variational assimilation of in situ continuous measurements of CO2 atmospheric mole fractions. Averaged over monthly periods and over the whole domain, the misfits are in good agreement with the theoretical uncertainties for prior and inverted NEE, and pass the chi-square test for the variance at the 30% and 5% significance levels respectively, despite the scale mismatch and the independence between the prior (respectively inverted) NEE and the flux measurements. The theoretical uncertainty reduction for the monthly NEE at the measurement sites is 53% while the inversion decreases the standard deviation of the misfits by 38%. These results build confidence in the NEE estimates at the European/monthly scales and in their theoretical uncertainty from the regional inverse modelling system. However, the uncertainties at the monthly (respectively annual) scale remain larger than the amplitude of the inter-annual variability of monthly (respectively annual) fluxes, so that this study does not engender confidence in the inter-annual variations. The uncertainties at the monthly scale are significantly smaller than the seasonal variations. The seasonal cycle of the inverted fluxes is thus reliable. In particular, the CO2 sink period over the European continent likely ends later than represented by the prior ecosystem model.
- Published
- 2013
26. Letter tot the editor: Iconic CO2 Time Series at Risk
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Houweling, S., Badawy, B., Baker, D.F., Basu, S., Belikov, D., Bergamaschi, P., Bousquet, P., Broquet, G., Butler, T., Canadell, J.G., Chen, J., Chevallier, F., Ciais, P., Collatz, G.J., Denning, S., Engelen, R., Enting, I.G., Fischer, M.L., Fraser, A., Gerbig, C., Gloor, M., Jacobson, A.R., Jones, D.B.A., Heimann, M., Khalil, A., Kaminski, T., Kasibhatla, P.S., Krakauer, N.Y., Krol, M., Maki, T., Maksyutov, S., Manning, A., Meesters, A., Miller, J.B., Palmer, P.I., Patra, P., Peters, W., Peylin, P., Poussi, Z., Prather, M.J., Randerson, J.T., Rockmann, T., Rodenbeck, C., Sarmiento, J.L., Schimel, D.S., Scholze, M., Schuh, A., Suntharalingam, P., Takahashi, T., Turnbull, J., Yurganov, L., and Vermeulen, A.
- Subjects
Meteorologie en Luchtkwaliteit ,WIMEK ,Meteorology and Air Quality ,Life Science - Published
- 2012
27. On the ability of a global atmospheric inversion to constrain variations of CO<sub>2</sub> fluxes over Amazonia
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Molina, L., primary, Broquet, G., additional, Imbach, P., additional, Chevallier, F., additional, Poulter, B., additional, Bonal, D., additional, Burban, B., additional, Ramonet, M., additional, Gatti, L. V., additional, Wofsy, S. C., additional, Munger, J. W., additional, Dlugokencky, E., additional, and Ciais, P., additional
- Published
- 2015
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28. Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant
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Yver Kwok, C. E., primary, Müller, D., additional, Caldow, C., additional, Lebègue, B., additional, Mønster, J. G., additional, Rella, C. W., additional, Scheutz, C., additional, Schmidt, M., additional, Ramonet, M., additional, Warneke, T., additional, Broquet, G., additional, and Ciais, P., additional
- Published
- 2015
- Full Text
- View/download PDF
29. Supplementary material to "Decadal trends in global CO emissions as seen by MOPITT"
- Author
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Yin, Y., primary, Chevallier, F., additional, Ciais, P., additional, Broquet, G., additional, Fortems-Cheiney, A., additional, Pison, I., additional, and Saunois, M., additional
- Published
- 2015
- Full Text
- View/download PDF
30. On the potential of ICOS atmospheric CO2 measurement network for the estimation of the biogenic CO2 budget of Europe
- Author
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Kadygrov, N., primary, Broquet, G., additional, Chevallier, F., additional, Rivier, L., additional, Gerbig, C., additional, and Ciais, P., additional
- Published
- 2015
- Full Text
- View/download PDF
31. Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant
- Author
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Yver-Kwok, C. E., primary, Müller, D., additional, Caldow, C., additional, Lebègue, B., additional, Mønster, J. G., additional, Rella, C. W., additional, Scheutz, C., additional, Schmidt, M., additional, Ramonet, M., additional, Warneke, T., additional, Broquet, G., additional, and Ciais, P., additional
- Published
- 2015
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- View/download PDF
32. An attempt at estimating Paris area CO<sub>2</sub> emissions from atmospheric concentration measurements
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Bréon, F. M., primary, Broquet, G., additional, Puygrenier, V., additional, Chevallier, F., additional, Xueref-Remy, I., additional, Ramonet, M., additional, Dieudonné, E., additional, Lopez, M., additional, Schmidt, M., additional, Perrussel, O., additional, and Ciais, P., additional
- Published
- 2015
- Full Text
- View/download PDF
33. Current systematic carbon-cycle observations and the need for implementing a policy-relevant carbon observing system
- Author
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Ciais, P., primary, Dolman, A. J., additional, Bombelli, A., additional, Duren, R., additional, Peregon, A., additional, Rayner, P. J., additional, Miller, C., additional, Gobron, N., additional, Kinderman, G., additional, Marland, G., additional, Gruber, N., additional, Chevallier, F., additional, Andres, R. J., additional, Balsamo, G., additional, Bopp, L., additional, Bréon, F.-M., additional, Broquet, G., additional, Dargaville, R., additional, Battin, T. J., additional, Borges, A., additional, Bovensmann, H., additional, Buchwitz, M., additional, Butler, J., additional, Canadell, J. G., additional, Cook, R. B., additional, DeFries, R., additional, Engelen, R., additional, Gurney, K. R., additional, Heinze, C., additional, Heimann, M., additional, Held, A., additional, Henry, M., additional, Law, B., additional, Luyssaert, S., additional, Miller, J., additional, Moriyama, T., additional, Moulin, C., additional, Myneni, R. B., additional, Nussli, C., additional, Obersteiner, M., additional, Ojima, D., additional, Pan, Y., additional, Paris, J.-D., additional, Piao, S. L., additional, Poulter, B., additional, Plummer, S., additional, Quegan, S., additional, Raymond, P., additional, Reichstein, M., additional, Rivier, L., additional, Sabine, C., additional, Schimel, D., additional, Tarasova, O., additional, Valentini, R., additional, Wang, R., additional, van der Werf, G., additional, Wickland, D., additional, Williams, M., additional, and Zehner, C., additional
- Published
- 2014
- Full Text
- View/download PDF
34. An attempt at estimating Paris area CO<sub>2</sub> emissions from atmospheric concentration measurements
- Author
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Bréon, F. M., primary, Broquet, G., additional, Puygrenier, V., additional, Chevallier, F., additional, Xueref-Rémy, I., additional, Ramonet, M., additional, Dieudonné, E., additional, Lopez, M., additional, Schmidt, M., additional, Perrussel, O., additional, and Ciais, P., additional
- Published
- 2014
- Full Text
- View/download PDF
35. Constraining CO2 emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia
- Author
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Konovalov, I. B., primary, Berezin, E. V., additional, Ciais, P., additional, Broquet, G., additional, Beekmann, M., additional, Hadji-Lazaro, J., additional, Clerbaux, C., additional, Andreae, M. O., additional, Kaiser, J. W., additional, and Schulze, E.-D., additional
- Published
- 2014
- Full Text
- View/download PDF
36. CarbonCGI road map to observe faint GHG source's emissions with high resolution observing system.
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Siméoni, D., Graziosi, F., Broquet, G., Kumar, P., Ciais, P., Vergely, J. L., Ferron, S., Khodnevych, V., Carlavan, M., Chétrite, B., Tetaz, N., Delzenne, C., Guercio, N., Boesch, H., Vogel, L., Mariani, F., Windpassinger, R., and Sierk, B.
- Published
- 2022
- Full Text
- View/download PDF
37. Estimation of waste water treatment plant methane emissions: methodology and results from a short campaign
- Author
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Yver-Kwok, C. E., primary, Müller, D., additional, Caldow, C., additional, Lebegue, B., additional, Mønster, J. G., additional, Rella, C. W., additional, Scheutz, C., additional, Schmidt, M., additional, Ramonet, M., additional, Warneke, T., additional, Broquet, G., additional, and Ciais, P., additional
- Published
- 2013
- Full Text
- View/download PDF
38. Current systematic carbon cycle observations and needs for implementing a policy-relevant carbon observing system
- Author
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Ciais, P., primary, Dolman, A. J., additional, Bombelli, A., additional, Duren, R., additional, Peregon, A., additional, Rayner, P. J., additional, Miller, C., additional, Gobron, N., additional, Kinderman, G., additional, Marland, G., additional, Gruber, N., additional, Chevallier, F., additional, Andres, R. J., additional, Balsamo, G., additional, Bopp, L., additional, Bréon, F.-M., additional, Broquet, G., additional, Dargaville, R., additional, Battin, T. J., additional, Borges, A., additional, Bovensmann, H., additional, Buchwitz, M., additional, Butler, J., additional, Canadell, J. G., additional, Cook, R. B., additional, DeFries, R., additional, Engelen, R., additional, Gurney, K. R., additional, Heinze, C., additional, Heimann, M., additional, Held, A., additional, Henry, M., additional, Law, B., additional, Luyssaert, S., additional, Miller, J., additional, Moriyama, T., additional, Moulin, C., additional, Myneni, R. B., additional, Nussli, C., additional, Obersteiner, M., additional, Ojima, D., additional, Pan, Y., additional, Paris, J.-D., additional, Piao, S. L., additional, Poulter, B., additional, Plummer, S., additional, Quegan, S., additional, Raymond, P., additional, Reichstein, M., additional, Rivier, L., additional, Sabine, C., additional, Schimel, D., additional, Tarasova, O., additional, Valentini, R., additional, van der Werf, G., additional, Wickland, D., additional, Williams, M., additional, and Zehner, C., additional
- Published
- 2013
- Full Text
- View/download PDF
39. Regional inversion of CO2 ecosystem fluxes from atmospheric measurements: reliability of the uncertainty estimates
- Author
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Broquet, G., primary, Chevallier, F., additional, Bréon, F.-M., additional, Alemanno, M., additional, Apadula, F., additional, Hammer, S., additional, Haszpra, L., additional, Meinhardt, F., additional, Necki, J., additional, Piacentino, S., additional, Ramonet, M., additional, Schmidt, M., additional, Thompson, R. L., additional, Vermeulen, A. T., additional, Yver, C., additional, and Ciais, P., additional
- Published
- 2013
- Full Text
- View/download PDF
40. Analysis of the potential of near ground measurements of CO2 and CH4 in London, UK for the monitoring of city-scale emissions using an atmospheric transport model.
- Author
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Boon, A., Broquet, G., Clifford, D. J., Chevallier, F., Butterfield, D. M., Pison, I., Ramonet, M., Paris, J. D., and Ciais, P.
- Abstract
Carbon dioxide (CO
2 ) and methane (CH4 ) mole fractions were measured at four near ground sites located in and around London during the summer of 2012 in view to investigate the potential of assimilating such measurements in an atmospheric inversion system for the monitoring of the CO2 and CH4 emissions in the London area. These data were analysed and compared with simulations using a modelling framework suited to building an inversion system: a 2 km horizontal resolution South of England configuration of the transport model CHIMERE driven by European Centre for Medium-Range Weather Forecasting (ECMWF) meteorological forcing, coupled to a 1 km horizontal resolution emission inventory (the UK National Atmospheric Emission Inventory). First comparisons reveal that local sources have a large impact on measurements and these local sources cannot be represented in the model at 2 km resolution. We evaluate methods to minimise some of the other critical sources of misfits between the observation data and the model simulation that overlap the signature of the errors in the emission inventory. These methods should make it easier to identify the corrections that should be applied to the inventory. Analysis is supported by observations from meteorological sites around the city and a three-week period of atmospheric mixing layer height estimations from lidar measurements. The difficulties of modelling the mixing layer depth and thus CO2 and CH4 concentrations during the night, morning and late afternoon led us to focus on the afternoon period for all further analyses. The misfits between observations and model simulations are high for both CO2 and CH4 (i.e., their root mean square (RMS) is between 8 and 12 parts per million (ppm) for CO2 and between 30 and 55 parts per billion (ppb) for CH4 at a given site). By analysing the gradients between the urban sites and a suburban or rural reference site, we are able to decrease the impact of uncertainties in the fluxes and transport outside the London area and in the model domain boundary conditions, and to better focus attention on the signature of London urban CO2 and CH4 emissions. This considerably improves the statistical agreement between the model and observations for CO2 (model-data RMS misfit of between 3 and 7 ppm) and to a lesser degree for CH4 (model-data RMS misfit of between 29 and 38 ppb). Between one of the urban sites and either reference site, selecting the gradients during periods wherein the reference site is upwind of the urban site further decreases the statistics of the misfits in general even though not systematically. In a final attempt to focus on the signature of the city anthropogenic emission in the mole fraction measurements, we use a theoretical ratio of gradients of CO to gradients of CO2 from fossil fuel emissions in the London area to diagnose observation based fossil fuel CO2 gradients, and compare them with the modelled ones. This estimate increases the consistency between the model and the measurements when considering one of the urban sites, but not when considering the other. While this study evaluates different approaches for increasing the consistency between the mesoscale model and the near ground data, and manages to decrease the random component of the analysed model data misfits to an extent that should not be prohibitive to extracting the signal from the London urban emissions, large biases remain in the final misfits. These biases are likely to be due to local emissions, to which the urban near ground sites are highly sensitive. This questions our current ability to exploit urban near ground data for the atmospheric inversion of city emissions based on models at spatial resolution coarser than 2 km. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
41. On the potential of the ICOS atmospheric CO2 measurement network for estimating the biogenic CO2 budget of Europe.
- Author
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Kadygrov, N., Broquet, G., Chevallier, F., Rivier, L., Gerbig, C., and Ciais, P.
- Subjects
ATMOSPHERIC carbon dioxide ,ATMOSPHERIC models ,ECOSYSTEMS ,DATA analysis ,COMPUTER simulation ,BIOMASS ,MATHEMATICAL models - Abstract
We present a performance assessment of the European Integrated Carbon Observing System (ICOS) atmospheric network for constraining European biogenic CO
2 fluxes (hereafter net ecosystem exchange, NEE). The performance of the network is assessed in terms of uncertainty in the fluxes, using a state-of-the-art mesoscale variational atmospheric inversion system assimilating hourly averages of atmospheric data to solve for NEE at 6 h and 0.5° resolution. The performance of the ICOS atmospheric network is also assessed in terms of uncertainty reduction compared to typical uncertainties in the flux estimates from ecosystem models, which are used as prior information by the inversion. The uncertainty in inverted fluxes is computed for two typical periods representative of northern summer and winter conditions in July and in December 2007, respectively. These computations are based on a observing system simulation experiment (OSSE) framework. We analyzed the uncertainty in a 2-week-mean NEE as a function of the spatial scale with a focus on the model native grid scale (0.5°), the country scale and the European scale (including western Russia and Turkey). Several network configurations, going from 23 to 66 sites, and different configurations of the prior uncertainties and atmospheric model transport errors are tested in order to assess and compare the improvements that can be expected in the future from the extension of the network, from improved prior information or transport models. Assimilating data from 23 sites (a network comparable to presentday capability) with errors estimated from the present prior information and transport models, the uncertainty reduction on a 2-week-mean NEE should range between 20 and 50% for 0.5° resolution grid cells in the best sampled area encompassing eastern France and western Germany. At the European scale, the prior uncertainty in a 2-week-mean NEE is reduced by 50% (66%), down to ~43 TgC month-1 (26 TgC month-1 ) in July (December). Using a larger network of 66 stations, the prior uncertainty of NEE is reduced by the inversion by 64% (down to ~33 TgC month-1 ) in July and by 79%(down to ~15 TgC month-1 ) in December. When the results are integrated over the well-observed western European domain, the uncertainty reduction shows no seasonal variability. The effect of decreasing the correlation length of the prior uncertainty, or of reducing the transport model errors compared to their present configuration (when conducting real-data inversion cases) can be larger than that of the extension of the measurement network in areas where the 23 station observation network is the densest. We show that with a configuration of the ICOS atmospheric network containing 66 sites that can be expected on the long-term, the uncertainties in a 2-week-mean NEE will be reduced by up to 50-80% for countries like Finland, Germany, France and Spain, which could significantly improvement (and at least a high complementarity to) our knowledge of NEE derived from biomass and soil carbon inventories at multi-annual scales. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
42. Atmospheric inversion for cost effective quantification of city CO2 emissions.
- Author
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Wu, L., Broquet, G., Ciais, P., Bellassen, V., Vogel, F., Chevallier, F., Xueref-Remy, I., and Wang, Y.
- Abstract
Cities, currently covering only a very small portion (< 3 %) of the world's land surface, directly release to the atmosphere about 44% of global energy-related CO
2 , and are associated with 71-76% of CO2 emissions from global final energy use. Although many cities have set voluntary climate plans, their CO2 emissions are not evaluated by Monitoring, Reporting and Verification (MRV) procedures that play a key role for market- or policy-based mitigation actions. Here we propose a monitoring tool that could support the development of such procedures at the city scale. It is based on an atmospheric inversion method that exploits inventory data and continuous atmospheric CO2 concentration measurements from a network of stations within and around cities to estimate city CO2 emissions. We examine the cost-effectiveness and the performance of such a tool. The instruments presently used to measure CO2 concentrations at research stations are expensive. However, cheaper sensors are currently developed and should be useable for the monitoring of CO2 emissions from a megacity in the near-term. Our assessment of the inversion method is thus based on the use of several types of hypothetical networks, with a range of numbers of sensors sampling at 25ma.g.l. The study case for this assessment is the monitoring of the emissions of the Paris metropolitan area (12 million inhabitants and 11.4 TgC emitted in 2010) during the month of January 2011. The performance of the inversion is evaluated in terms of uncertainties in the estimates of total and sectoral CO2 emissions. These uncertainties are compared to a notional ambitious target to diagnose annual total city emissions with an uncertainty of 5% (2-sigma). We find that, with 10 stations only, which is the typical size of current pilot networks that are deployed in some cities, the uncertainty for the 1-month total city CO2 emissions is significantly reduced by the inversion by 42% but still corresponds to an annual uncertainty that is two times larger than the target of 5%. By extending the network from 10 to 70 stations, the inversion can meet this requirement. As for major sectoral CO2 emissions, the uncertainties in the inverted emissions using 70 stations are reduced significantly over that obtained using 10 stations by 32% for commercial and residential buildings, by 33% for road transport and by 18% for the production of energy by power plants, respectively. With 70 stations, the uncertainties from the inversion become of 15% 2-sigma annual uncertainty for dispersed building emissions, and 18% for emissions from road transport and energy production. The inversion performance could be further improved by optimal design of station locations and/or by assimilating additional atmospheric measurements of species that are co-emitted with CO2 by fossil fuel combustion processes with a specific signature from each sector, such as carbon monoxide (CO). Atmospheric inversions based on continuous CO2 measurements from a large number of cheap sensors can thus de liver a valuable quantification tool for the monitoring and/or the verification of city CO2 emissions (baseline) and CO2 emission reductions (commitments). [ABSTRACT FROM AUTHOR]- Published
- 2015
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43. On the ability of a global atmospheric inversion to constrain variations of CO2 fluxes over Amazonia.
- Author
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Molina, L., Broquet, G., Imbach, P., Chevallier, F., Poulter, B., Bonal, D., Burban, B., Ramonet, M., Gatti, L. V., Wofsy, S. C., Munger, J. W., Dlugokencky, E., and Ciais, P.
- Subjects
ATMOSPHERIC transport ,ATMOSPHERIC models ,ATMOSPHERIC carbon dioxide ,CLIMATE change - Abstract
The exchanges of carbon, water and energy between the atmosphere and the Amazon basin have global implications for the current and future climate. Here, the global atmospheric inversion system of the Monitoring of Atmospheric Composition and Climate (MACC) service is used to study the seasonal and interannual variations of biogenic CO
2 fluxes in Amazonia during the period 2002-2010. The system assimilated surface measurements of atmospheric CO2 mole fractions made at more than 100 sites over the globe into an atmospheric transport model. The present study adds measurements from four surface stations located in tropical South America, a region poorly covered by CO2 observations. The estimates of net ecosystem exchange (NEE) optimized by the inversion are compared to an independent estimate of NEE upscaled from eddy-covariance flux measurements in Amazonia. They are also qualitatively evaluated against reports on the seasonal and interannual variations of the land sink in South America from the scientific literature. We attempt at assessing the impact on NEE of the strong droughts in 2005 and 2010 (due to severe and longer-thanusual dry seasons) and the extreme rainfall conditions registered in 2009. The spatial variations of the seasonal and interannual variability of optimized NEE are also investigated. While the inversion supports the assumption of strong spatial heterogeneity of these variations, the results reveal critical limitations of the coarse-resolution transport model, the surface observation network in South America during the recent years and the present knowledge of modelling uncertainties in South America that prevent our inversion from capturing the seasonal patterns of fluxes across Amazonia. However, some patterns from the inversion seem consistent with the anomaly of moisture conditions in 2009. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
44. Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant.
- Author
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Kwok, C. E. Yver, Müller, D., Caldow, C., Lebègue, B., Mønster, J. G., Rella, C. W., Scheutz, C., Schmidt, M., Ramonet, M., Warneke, T., Broquet, G., and Ciais, P.
- Subjects
METHANE ,EMISSIONS (Air pollution) ,SEWAGE disposal plants ,FOURIER transform infrared spectroscopy ,SLUDGE management - Abstract
This study presents two methods for estimating methane emissions from a waste water treatment plant (WWTP) along with results from a measurement campaign at a WWTP in Valence, France. These methods, chamber measurements and tracer release, rely on Fourier transform infrared spectroscopy and cavity ring-down spectroscopy instruments. We show that the tracer release method is suitable for quantifying facility-and some process-scale emissions, while the chamber measurements provide insight into individual process emissions. Uncertainties for the two methods are described and discussed. Applying the methods to CH
4 emissions of the WWTP, we confirm that the open basins are not a major source of CH4 on the WWTP (about 10% of the total emissions), but that the pretreatment and sludge treatment are the main emitters. Overall, the waste water treatment plant is representative of an average French WWTP. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
45. An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements.
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Bréon, F. M., Broquet, G., Puygrenier, V., Chevallier, F., Xueref-Remy, I., Ramonet, M., Dieudonné, E., Lopez, M., Schmidt, M., Perrussel, O., and Ciais, P.
- Subjects
ATMOSPHERIC carbon dioxide ,CARBON dioxide mitigation ,ATMOSPHERIC models ,AIR quality ,BOUNDARY value problems - Abstract
Atmospheric concentration measurements are used to adjust the daily to monthly budget of fossil fuel CO
2 emissions of the Paris urban area from the prior estimates established by the Airparif local air quality agency. Five atmospheric monitoring sites are available, including one at the top of the Eiffel Tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model with a spatial resolution of 2 km with boundary conditions from a global coarse grid transport model. The inversion adjusts prior knowledge about the anthropogenic and biogenic CO2 fluxes from the Airparif inventory and an ecosystem model, respectively, with corrections at a temporal resolution of 6 h, while keeping the spatial distribution from the emission inventory. These corrections are based on assumptions regarding the temporal autocorrelation of prior emissions uncertainties within the daily cycle, and from day to day. The comparison of the measurements against the atmospheric transport simulation driven by the a priori CO2 surface fluxes shows significant differences upwind of the Paris urban area, which suggests a large and uncertain contribution from distant sources and sinks to the CO2 concentration variability. This contribution advocates that the inversion should aim at minimising model-data misfits in upwind-downwind gradients rather than misfits in mole fractions at individual sites. Another conclusion of the direct model-measurement comparison is that the CO2 variability at the top of the Eiffel Tower is large and poorly represented by the model for most wind speeds and directions. The model's inability to reproduce the CO2 variability at the heart of the city makes such measurements ill-suited for the inversion. This and the need to constrain the budgets for the whole city suggests the assimilation of upwind-downwind mole fraction gradients between sites at the edge of the urban area only. The inversion significantly improves the agreement between measured and modelled concentration gradients. Realistic emissions are retrieved for two 30-day periods and suggest a significant overestimate by the AirParif inventory. Similar inversions over longer periods are necessary for a proper evaluation of the optimised CO2 emissions against independent data. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
46. Human papillomavirus (HPV) DNA assay as an adjunct to liquid-based Pap test in the diagnostic triage of women with an abnormal Pap smear
- Author
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Vassilakos, P., primary, de Marval, F., additional, Muñoz, M., additional, Broquet, G., additional, and Campana, A., additional
- Published
- 1998
- Full Text
- View/download PDF
47. Estimation of waste water treatment plant methane emissions: methodology and results from a short campaign.
- Author
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Yver-Kwok, C. E., Müller, D., Caldow, C., Lebegue, B., Mønster, J. G., Rella, C. W., Scheutz, C., Schmidt, M., Ramonet, M., Warneke, T., Broquet, G., and Ciais, P.
- Subjects
WATER treatment plants ,METHANE ,EMISSIONS (Air pollution) ,METHODOLOGY ,FOURIER transform infrared spectroscopy - Abstract
This paper describes different methods to estimate methane emissions at different scales. These methods are applied to a waste water treatment plant (WWTP) located in Valence, France. We show that Fourier Transform Infrared (FTIR) measurements as well as Cavity Ring Down Spectroscopy (CRDS) can be used to measure emissions from the process to the regional scale. To estimate the total emissions, we investigate a tracer release method (using C
2 H2 ) and the Radon tracer method (using222 Rn). For process-scale emissions, both tracer release and chamber techniques were used. We show that the tracer release method is suitable to quantify facility- and some process scale emissions, while the Radon tracer method encompasses not only the treatment station but also a large area around. Thus the Radon tracer method is more representative of the regional emissions around the city. Uncertainties for each method are described. Applying the methods to CH4 emissions, we find that the main source of emissions of the plant was not identified with certainty during this short campaign, although the primary source of emissions is likely to be from solid sludge. Overall, the waste water treatment plant represents a small part (3 %) of the methane emissions of the city of Valence and its surroundings,which is in agreement with the national inventories. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
48. Regional inversion of CO2 ecosystem fluxes from atmospheric measurements: reliability of the uncertainty estimates.
- Author
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Broquet, G., Chevallier, F., Bréon, F.-M., Kadygrov, N., Alemanno, M., Apadula, F., Hammer, S., Haszpra, L., Meinhardt, F., Morguí, J. A., Necki, J., Piacentino, S., Ramonet, M., Schmidt, M., Thompson, R. L., Vermeulen, A. T., Yver, C., and Ciais, P.
- Subjects
ATMOSPHERIC carbon dioxide ,ECOSYSTEMS ,UNCERTAINTY (Information theory) ,PARAMETER estimation ,BAYESIAN analysis ,ATMOSPHERIC transport ,ATMOSPHERIC models - Abstract
The Bayesian framework of CO2 flux inversions permits estimates of the retrieved flux uncertainties. Here, the reliability of these theoretical estimates is studied through a comparison against the misfits between the inverted fluxes and independent measurements of the CO2 Net Ecosystem Exchange (NEE) made by the eddy covariance technique at local (few hectares) scale. Regional inversions at 0.5° resolution are applied for the western European domain where 50 eddy covariance sites are operated. These inversions are conducted for the period 2002-2007. They use a mesoscale atmospheric transport model, a prior estimate of the NEE from a terrestrial ecosystem model and rely on the variational assimilation of in situ continuous measurements of CO2 atmospheric mole fractions. Averaged over monthly periods and over the whole domain, the misfits are in good agreement with the theoretical uncertainties for prior and inverted NEE, and pass the chi-square test for the variance at the 30% and 5% significance levels respectively, despite the scale mismatch and the independence between the prior (respectively inverted) NEE and the flux measurements. The theoretical uncertainty reduction for the monthly NEE at the measurement sites is 53% while the inversion decreases the standard deviation of the misfits by 38 %. These results build confidence in the NEE estimates at the European/monthly scales and in their theoretical uncertainty from the regional inverse modelling system. However, the uncertainties at the monthly (respectively annual) scale remain larger than the amplitude of the inter-annual variability of monthly (respectively annual) fluxes, so that this study does not engender confidence in the inter-annual variations. The uncertainties at the monthly scale are significantly smaller than the seasonal variations. The seasonal cycle of the inverted fluxes is thus reliable. In particular, the CO
2 sink period over the European continent likely ends later than represented by the prior ecosystem model. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
49. Current systematic carbon cycle observations and needs for implementing a policy-relevant carbon observing system.
- Author
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Ciais, P., Dolman, A. J., Bombelli, A., Duren, R., Peregon, A., Rayner, P. J., Miller, C., Gobron, N., Kinderman, G., Marland, G., Gruber, N., Chevallier, F., Andres, R. J., Balsamo, G., Bopp, L., Bréon, F.-M., Broquet, G., Dargaville, R., Battin, T. J., and Borges, A.
- Subjects
CARBON cycle ,GREENHOUSE gas mitigation ,CARBON sequestration ,ENVIRONMENTAL policy ,ATMOSPHERE ,DATA analysis - Abstract
A globally integrated carbon observation and analysis system is needed to improve the fundamental understanding of the global carbon cycle, to improve our ability to project future changes, and to verify the effectiveness of policies aiming to reduce greenhouse gas emissions and increase carbon sequestration. Building an integrated carbon observation system requires transformational advances from the existing sparse, exploratory framework towards a dense, robust, and sustained system in all components: anthropogenic emissions, the atmosphere, the ocean, and the terrestrial biosphere. The goal of this study is to identify the current state of carbon observations and needs for a global integrated carbon observation system that can be built in the next decade. A key conclusion is the substantial expansion (by several orders of magnitude) of the ground-based observation networks required to reach the high spatial resolution for CO
2 and CH4 fluxes, and for carbon stocks for addressing policy relevant objectives, and attributing flux changes to underlying processes in each region. In order to establish flux and stock diagnostics over remote areas such as the southern oceans, tropical forests and the Arctic, in situ observations will have to be complemented with remote-sensing measurements. Remote sensing offers the advantage of dense spatial coverage and frequent revisit. A key challenge is to bring remote sensing measurements to a level of long-term consistency and accuracy so that they can be efficiently combined in models to reduce uncertainties, in synergy with ground-based data. Bringing tight observational constraints on fossil fuel and land use change emissions will be the biggest challenge for deployment of a policy-relevant integrated carbon observation system. This will require in-situ and remotely sensed data at much higher resolution and density than currently achieved for natural fluxes, although over a small land area (cities, industrial sites, power plants), as well as the inclusion of fossil fuel CO2 proxy measurements such as radiocarbon in CO2 and carbon-fuel combustion tracers. Additionally, a policy relevant carbon monitoring system should also provide mechanisms for reconciling regional top-down (atmosphere-based) and bottom-up (surface-based) flux estimates across the range of spatial and temporal scales relevant to mitigation policies. The success of the system will rely on long-term commitments to monitoring, on improved international collaboration to fill gaps in the current observations, on sustained efforts to improve access to the different data streams and make databases inter-operable, and on the calibration of each component of the system to agreed-upon international scales. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
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50. Analysis of the Anthropogenic and Biogenic NOxEmissions Over 2008–2017: Assessment of the Trends in the 30 Most Populated Urban Areas in Europe
- Author
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Fortems‐Cheiney, A., Broquet, G., Pison, I., Saunois, M., Potier, E., Berchet, A., Dufour, G., Siour, G., Denier van der Gon, H., Dellaert, S. N. C., and Boersma, K. F.
- Abstract
We use the OMI‐QA4ECV‐v1.1 NO2tropospheric columns over the 10‐year 2008–2017 period to confront satellite‐based trends in NO2concentrations to those from the state‐of‐the‐art regional chemistry‐transport model CHIMERE and to evaluate the bottom‐up anthropogenic and biogenic NOxemissions in Europe. A focus is made for the 30 most populated urban areas in Europe. Over urban areas in Western Europe, except for coastal cities, OMI confirms the drop in the simulated CHIMERE NO2tropospheric columns based on the latest country emission official reporting. OMI hardly shows significant negative trends over Central and Eastern Europe urban areas. Increasing biogenic emissions helps reconciling CHIMERE and OMI trends over urban areas in Central Europe and over rural areas, confirming the importance of accounting for non‐anthropogenic emissions to assess long‐term trends. Over Eastern Europe, our results question emission reductions estimated for particular sectors and in particular the road transport, public power, and industrial emissions. We evaluate anthropogenic and biogenic nitrogen oxides (NOx) emissions in Europe by analyzing nitrogen dioxide (NO2) 10‐yr trends both from satellite observations and from simulations. A focus is made for the 30 most populated urban areas in Europe, particularly exposed to air pollution. The similarities and discrepancies between simulations and satellite observations indeed must be investigated. It is important particularly for policy implications as anthropogenic emissions are based on the official reported emissions form the basis for negotiation on emission reductions in the EU and are used to assess if countries meet their agreed emission ceilings. Over urban areas in Western Europe, OMI confirms the drop of the simulated CHIMERE NO2tropospheric vertical column density columns, based on the latest country emission reportingIncreasing biogenic emissions reconciles CHIMERE and OMI over urban areas in Central Europe and over rural areas, confirming their importance to assess long‐term trendsOver Eastern Europe, our results question emission reductions estimated for particular sectors such as road transport, public power and industrial emissions Over urban areas in Western Europe, OMI confirms the drop of the simulated CHIMERE NO2tropospheric vertical column density columns, based on the latest country emission reporting Increasing biogenic emissions reconciles CHIMERE and OMI over urban areas in Central Europe and over rural areas, confirming their importance to assess long‐term trends Over Eastern Europe, our results question emission reductions estimated for particular sectors such as road transport, public power and industrial emissions
- Published
- 2021
- Full Text
- View/download PDF
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