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Your search keyword '"O'Dell, Christopher"' showing total 13 results
Start Over Author "O'Dell, Christopher" Journal geophysical research letters
13 results on '"O'Dell, Christopher"'

1. Local Anomalies in the Column‐Averaged Dry Air Mole Fractions of Carbon Dioxide Across the Globe During the First Months of the Coronavirus Recession

Author

Chevallier, Frédéric, Zheng, Bo, Broquet, Grégoire, Ciais, Philippe, Liu, Zhu, Davis, Steven J, Deng, Zhu, Wang, Yilong, Bréon, François‐Marie, and O'Dell, Christopher W

Subjects
Climate Action, carbon dioxide, emissions, OCO&#8208, 2, Paris Agreement, plume, satellite, OCO‐2, Meteorology & Atmospheric Sciences
Abstract

We use a global transport model and satellite retrievals of the carbon dioxide (CO2) column average to explore the impact of CO2 emissions reductions that occurred during the economic downturn at the start of the Covid-19 pandemic. The changes in the column averages are substantial in a few places of the model global grid, but the induced gradients are most often less than the random errors of the retrievals. The current necessity to restrict the quality-assured column retrievals to almost cloud-free areas appears to be a major obstacle in identifying changes in CO2 emissions. Indeed, large changes have occurred in the presence of clouds, and in places that were cloud free in 2020, the comparison with previous years is hampered by different cloud conditions during these years. We therefore recommend to favor all-weather CO2 monitoring systems, at least in situ, to support international efforts to reduce emissions.

Published
2020

3. Influence of differences in current GOSAT XCO2 retrievals on surface flux estimation

Author

Takagi, Hiroshi, Houweling, Sander, Andres, Robert J., Belikov, Dmitry, Bril, Andrey, Boesch, Hartmut, Butz, Andre, Guerlet, Sandrine, Hasekamp, Otto, Maksyutov, Shamil, Morino, Isamu, Oda, Tomohiro, O'Dell, Christopher W., Oshchepkov, Sergey, Parker, Robert, Saito, Makoto, Uchino, Osamu, Yokota, Tatsuya, Yoshida, Yukio, Valsala, Vinu, Earth and Climate, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
surface fluxes, column CO2 concentration, [SDU]Sciences of the Universe [physics], CO2 sources and sinks, SDG 13 - Climate Action, Earth Science, inverse modeling, GOSAT
Abstract

International audience; We investigated differences in the five currently-available datasets of column-integrated CO2 concentrations (XCO2) retrieved from spectral soundings collected by Greenhouse gases Observing SATellite (GOSAT) and assessed their impact on regional CO2 flux estimates. We did so by estimating the fluxes from each of the five XCO2 datasets combined with surface-based CO2 data, using a single inversion system. The five XCO2 datasets are available in raw and bias-corrected versions, and we found that the bias corrections diminish the range of the five coincident values by ~30% on average. The departures of the five individual inversion results (annual-mean regional fluxes based on XCO2-surface combined data) from the surface-data-only results were close to one another in some terrestrial regions where spatial coverage by each XCO2 dataset was similar. The mean of the five annual global land uptakes was 1.7 ± 0.3 GtC yr-1, and they were all smaller than the value estimated from the surface-based data alone.

Published
2014

5. Influence of differences in current GOSATXCO2retrievals on surface flux estimation

Author

Takagi, Hiroshi, primary, Houweling, Sander, additional, Andres, Robert J., additional, Belikov, Dmitry, additional, Bril, Andrey, additional, Boesch, Hartmut, additional, Butz, Andre, additional, Guerlet, Sandrine, additional, Hasekamp, Otto, additional, Maksyutov, Shamil, additional, Morino, Isamu, additional, Oda, Tomohiro, additional, O'Dell, Christopher W., additional, Oshchepkov, Sergey, additional, Parker, Robert, additional, Saito, Makoto, additional, Uchino, Osamu, additional, Yokota, Tatsuya, additional, Yoshida, Yukio, additional, and Valsala, Vinu, additional

Published
2014
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13. Toward robust and consistent regional CO2flux estimates from in situ and spaceborne measurements of atmospheric CO2

Author

Chevallier, Frédéric, Palmer, Paul I., Feng, Liang, Boesch, Hartmut, O'Dell, Christopher W., and Bousquet, Philippe

Abstract

We evaluate the robustness and consistency of global and regional posterior CO2flux estimates for 2010 inferred from two versions of bias‐corrected CO2column retrievals from the Japanese Greenhouse Gases Observing Satellite (GOSAT). Six satellite‐based inversions, generated from three atmospheric transport models and two independent Bayesian inference algorithms, facilitate a rigorous investigation of the uncertainty of the inverted fluxes. This ensemble shows hemispheric and regional differences in posterior flux estimates that are beyond 1 sigma uncertainties and in some regions are unrealistic. We recognize the importance of these satellite data in further understanding the contemporary carbon cycle but we argue that more resources should be invested in characterizing the errors of the prior fluxes, the systematic errors of the retrievals, and the systematic errors of the transport models, to improve confidence in the resulting posterior fluxes. Nine global CO2atmospheric inversions are comparedThe CO2fluxes inferred from the satellite data show limited realismThe satellite‐inferred fluxes show large sensitivity to all input information

Published
2014
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