TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements
To assess horizontal and vertical transports of methane (CH4) concentrations at different heights within the troposphere, we analyzed simulations by 12 chemistry transport models (CTMs) that participated in the TransCom-CH4 intercomparison experiment. Model results are compared with aircraft measure...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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John Wiley & Sons, Inc
2014
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| Online Access: | http://hdl.handle.net/1721.1/86957 https://orcid.org/0000-0001-5925-3801 |
| _version_ | 1811086093654687744 |
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| author | Saito, Ryu Patra, Prabir K. Sweeney, Colm Machida, Toshinobu Krol, Maarten Houweling, S. Bousquet, P. Agusti-Panareda, Anna Belikov, Dmitry Bergmann, Dan Bian, Huisheng Cameron-Smith, P. Chipperfield, M. P. Fortems-Cheiney, A. Fraser, A. Gatti, Luciana V. Gloor, E. Hess, Peter Kawa, Stephan R. Law, Rachel M. Locatelli, Robin Loh, Zoe Maksyutov, Shamil Meng, Lei Miller, John B. Palmer, Paul I. Prinn, Ronald G. Rigby, Matthew Wilson, Christopher |
| author2 | Massachusetts Institute of Technology. Center for Global Change Science |
| author_facet | Massachusetts Institute of Technology. Center for Global Change Science Saito, Ryu Patra, Prabir K. Sweeney, Colm Machida, Toshinobu Krol, Maarten Houweling, S. Bousquet, P. Agusti-Panareda, Anna Belikov, Dmitry Bergmann, Dan Bian, Huisheng Cameron-Smith, P. Chipperfield, M. P. Fortems-Cheiney, A. Fraser, A. Gatti, Luciana V. Gloor, E. Hess, Peter Kawa, Stephan R. Law, Rachel M. Locatelli, Robin Loh, Zoe Maksyutov, Shamil Meng, Lei Miller, John B. Palmer, Paul I. Prinn, Ronald G. Rigby, Matthew Wilson, Christopher |
| author_sort | Saito, Ryu |
| collection | MIT |
| description | To assess horizontal and vertical transports of methane (CH4) concentrations at different heights within the troposphere, we analyzed simulations by 12 chemistry transport models (CTMs) that participated in the TransCom-CH4 intercomparison experiment. Model results are compared with aircraft measurements at 13 sites in Amazon/Brazil, Mongolia, Pacific Ocean, Siberia/Russia, and United States during the period of 2001–2007. The simulations generally show good agreement with observations for seasonal cycles and vertical gradients. The correlation coefficients of the daily averaged model and observed CH4 time series for the analyzed years are generally larger than 0.5, and the observed seasonal cycle amplitudes are simulated well at most sites, considering the between-model variances. However, larger deviations show up below 2 km for the model-observation differences in vertical profiles at some locations, e.g., at Santarem, Brazil, and in the upper troposphere, e.g., at Surgut, Russia. Vertical gradients and concentrations are underestimated at Southern Great Planes, United States, and Santarem and overestimated at Surgut. Systematic overestimation and underestimation of vertical gradients are mainly attributed to inaccurate emission and only partly to the transport uncertainties. However, large differences in model simulations are found over the regions/seasons of strong convection, which is poorly represented in the models. Overall, the zonal and latitudinal variations in CH4 are controlled by surface emissions below 2.5 km and transport patterns in the middle and upper troposphere. We show that the models with larger vertical gradients, coupled with slower horizontal transport, exhibit greater CH4 interhemispheric gradients in the lower troposphere. These findings have significant implications for the future development of more accurate CTMs with the possibility of reducing biases in estimated surface fluxes by inverse modeling. |
| first_indexed | 2024-09-23T13:20:47Z |
| format | Article |
| id | mit-1721.1/86957 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:20:47Z |
| publishDate | 2014 |
| publisher | John Wiley & Sons, Inc |
| record_format | dspace |
| spelling | mit-1721.1/869572022-10-01T14:38:53Z TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements Saito, Ryu Patra, Prabir K. Sweeney, Colm Machida, Toshinobu Krol, Maarten Houweling, S. Bousquet, P. Agusti-Panareda, Anna Belikov, Dmitry Bergmann, Dan Bian, Huisheng Cameron-Smith, P. Chipperfield, M. P. Fortems-Cheiney, A. Fraser, A. Gatti, Luciana V. Gloor, E. Hess, Peter Kawa, Stephan R. Law, Rachel M. Locatelli, Robin Loh, Zoe Maksyutov, Shamil Meng, Lei Miller, John B. Palmer, Paul I. Prinn, Ronald G. Rigby, Matthew Wilson, Christopher Massachusetts Institute of Technology. Center for Global Change Science Prinn, Ronald G. Rigby, Matthew To assess horizontal and vertical transports of methane (CH4) concentrations at different heights within the troposphere, we analyzed simulations by 12 chemistry transport models (CTMs) that participated in the TransCom-CH4 intercomparison experiment. Model results are compared with aircraft measurements at 13 sites in Amazon/Brazil, Mongolia, Pacific Ocean, Siberia/Russia, and United States during the period of 2001–2007. The simulations generally show good agreement with observations for seasonal cycles and vertical gradients. The correlation coefficients of the daily averaged model and observed CH4 time series for the analyzed years are generally larger than 0.5, and the observed seasonal cycle amplitudes are simulated well at most sites, considering the between-model variances. However, larger deviations show up below 2 km for the model-observation differences in vertical profiles at some locations, e.g., at Santarem, Brazil, and in the upper troposphere, e.g., at Surgut, Russia. Vertical gradients and concentrations are underestimated at Southern Great Planes, United States, and Santarem and overestimated at Surgut. Systematic overestimation and underestimation of vertical gradients are mainly attributed to inaccurate emission and only partly to the transport uncertainties. However, large differences in model simulations are found over the regions/seasons of strong convection, which is poorly represented in the models. Overall, the zonal and latitudinal variations in CH4 are controlled by surface emissions below 2.5 km and transport patterns in the middle and upper troposphere. We show that the models with larger vertical gradients, coupled with slower horizontal transport, exhibit greater CH4 interhemispheric gradients in the lower troposphere. These findings have significant implications for the future development of more accurate CTMs with the possibility of reducing biases in estimated surface fluxes by inverse modeling. Japan Society for the Promotion of Science (JSPS/MEXT KAKENHI-A (grant 22241008)) Natural Environment Research Council (Great Britain) National Centre for Earth Observation (Great Britain) United States. National Aeronautics and Space Administration (NASA-AGAGE grant NNX07AE89G) Natural Environment Research Council (Great Britain) (Advanced Fellowship) Seventh Framework Programme (European Commission) ([FP7 THEME (SPA.2011.1.5-02)] under grant 283576 in the context of the MACC-II project (Monitoring Atmospheric Composition and Climate—Interim Implementation)) 2014-05-14T20:19:59Z 2014-05-14T20:19:59Z 2013-05 2013-03 Article http://purl.org/eprint/type/JournalArticle 2169897X http://hdl.handle.net/1721.1/86957 Saito, Ryu, Prabir K. Patra, Colm Sweeney, Toshinobu Machida, Maarten Krol, Sander Houweling, Philippe Bousquet, et al. “TransCom Model Simulations of Methane: Comparison of Vertical Profiles with Aircraft Measurements.” Journal of Geophysical Research: Atmospheres 118, no. 9 (May 16, 2013): 3891–3904. ©2013. American Geophysical Union. https://orcid.org/0000-0001-5925-3801 en_US http://dx.doi.org/10.1002/jgrd.50380 Journal of Geophysical Research: Atmospheres Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf John Wiley & Sons, Inc Other repository |
| spellingShingle | Saito, Ryu Patra, Prabir K. Sweeney, Colm Machida, Toshinobu Krol, Maarten Houweling, S. Bousquet, P. Agusti-Panareda, Anna Belikov, Dmitry Bergmann, Dan Bian, Huisheng Cameron-Smith, P. Chipperfield, M. P. Fortems-Cheiney, A. Fraser, A. Gatti, Luciana V. Gloor, E. Hess, Peter Kawa, Stephan R. Law, Rachel M. Locatelli, Robin Loh, Zoe Maksyutov, Shamil Meng, Lei Miller, John B. Palmer, Paul I. Prinn, Ronald G. Rigby, Matthew Wilson, Christopher TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements |
| title | TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements |
| title_full | TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements |
| title_fullStr | TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements |
| title_full_unstemmed | TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements |
| title_short | TransCom model simulations of methane: Comparison of vertical profiles with aircraft measurements |
| title_sort | transcom model simulations of methane comparison of vertical profiles with aircraft measurements |
| url | http://hdl.handle.net/1721.1/86957 https://orcid.org/0000-0001-5925-3801 |
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