Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling
A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH[subscript 4] model inter-comparison...
| Main Authors: | , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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Copernicus GmbH
2013
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| Online Access: | http://hdl.handle.net/1721.1/82927 https://orcid.org/0000-0001-5925-3801 |
| _version_ | 1811082702506426368 |
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| author | Locatelli, Robin Bousquet, P. Chevallier, F. Fortems-Cheiney, A. Szopa, S. Saunois, M. Agusti-Panareda, Anna Bergmann, D. Bian, H. Cameron-Smith, P. Chipperfield, M. P. Gloor, E. Houweling, S. Kawa, Stephan R. Krol, Maarten Patra, P. K. Saito, R. Wilson, C. Rigby, Matthew Prinn, Ronald G. |
| author2 | Massachusetts Institute of Technology. Center for Global Change Science |
| author_facet | Massachusetts Institute of Technology. Center for Global Change Science Locatelli, Robin Bousquet, P. Chevallier, F. Fortems-Cheiney, A. Szopa, S. Saunois, M. Agusti-Panareda, Anna Bergmann, D. Bian, H. Cameron-Smith, P. Chipperfield, M. P. Gloor, E. Houweling, S. Kawa, Stephan R. Krol, Maarten Patra, P. K. Saito, R. Wilson, C. Rigby, Matthew Prinn, Ronald G. |
| author_sort | Locatelli, Robin |
| collection | MIT |
| description | A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH[subscript 4] model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System) inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure) is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes.
In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr[superscript −1] at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr[superscript −1] in North America to 7 Tg yr[superscript −1] in Boreal Eurasia (from 23 to 48%, respectively). At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly question the consistency of transport model errors in current inverse systems.
Future inversions should include more accurately prescribed observation covariances matrices in order to limit the impact of transport model errors on estimated methane fluxes. |
| first_indexed | 2024-09-23T12:07:17Z |
| format | Article |
| id | mit-1721.1/82927 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T12:07:17Z |
| publishDate | 2013 |
| publisher | Copernicus GmbH |
| record_format | dspace |
| spelling | mit-1721.1/829272022-10-01T08:20:10Z Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling Locatelli, Robin Bousquet, P. Chevallier, F. Fortems-Cheiney, A. Szopa, S. Saunois, M. Agusti-Panareda, Anna Bergmann, D. Bian, H. Cameron-Smith, P. Chipperfield, M. P. Gloor, E. Houweling, S. Kawa, Stephan R. Krol, Maarten Patra, P. K. Saito, R. Wilson, C. Rigby, Matthew Prinn, Ronald G. Massachusetts Institute of Technology. Center for Global Change Science Rigby, Matthew Prinn, Ronald G. A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH[subscript 4] model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System) inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure) is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr[superscript −1] at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr[superscript −1] in North America to 7 Tg yr[superscript −1] in Boreal Eurasia (from 23 to 48%, respectively). At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly question the consistency of transport model errors in current inverse systems. Future inversions should include more accurately prescribed observation covariances matrices in order to limit the impact of transport model errors on estimated methane fluxes. 2013-12-13T19:50:57Z 2013-12-13T19:50:57Z 2013-10 2013-08 Article http://purl.org/eprint/type/JournalArticle 1680-7324 1680-7316 http://hdl.handle.net/1721.1/82927 Locatelli, R., P. Bousquet, F. Chevallier, A. Fortems-Cheiney, S. Szopa, M. Saunois, A. Agusti-Panareda, et al. “Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling.” Atmospheric Chemistry and Physics 13, no. 19 (October 8, 2013): 9917-9937. https://orcid.org/0000-0001-5925-3801 en_US http://dx.doi.org/10.5194/acp-13-9917-2013 Atmospheric Chemistry and Physics http://creativecommons.org/licenses/by/3.0/ application/pdf Copernicus GmbH |
| spellingShingle | Locatelli, Robin Bousquet, P. Chevallier, F. Fortems-Cheiney, A. Szopa, S. Saunois, M. Agusti-Panareda, Anna Bergmann, D. Bian, H. Cameron-Smith, P. Chipperfield, M. P. Gloor, E. Houweling, S. Kawa, Stephan R. Krol, Maarten Patra, P. K. Saito, R. Wilson, C. Rigby, Matthew Prinn, Ronald G. Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling |
| title | Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling |
| title_full | Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling |
| title_fullStr | Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling |
| title_full_unstemmed | Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling |
| title_short | Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling |
| title_sort | impact of transport model errors on the global and regional methane emissions estimated by inverse modelling |
| url | http://hdl.handle.net/1721.1/82927 https://orcid.org/0000-0001-5925-3801 |
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