Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1999.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2010
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| Online Access: | http://hdl.handle.net/1721.1/54436 |
| _version_ | 1811096583879524352 |
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| author | Jensen, Christopher D. (Christopher David), 1974- |
| author2 | Ronald G. Prinn. |
| author_facet | Ronald G. Prinn. Jensen, Christopher D. (Christopher David), 1974- |
| author_sort | Jensen, Christopher D. (Christopher David), 1974- |
| collection | MIT |
| description | Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1999. |
| first_indexed | 2024-09-23T16:46:00Z |
| format | Thesis |
| id | mit-1721.1/54436 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T16:46:00Z |
| publishDate | 2010 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/544362019-09-26T21:33:19Z Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities Terrestrial fluxes of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities Jensen, Christopher D. (Christopher David), 1974- Ronald G. Prinn. Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Earth, Atmospheric, and Planetary Sciences. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1999. Includes bibliographical references (p. 87-92). Current estimates of methyl bromide surface fluxes are inconsistent with the observed tropospheric mole fractions (9 to 10 ppt, globally averaged) and the calculated atmospheric lifetime (1.7 ± 0.2 years), with mid-range estimates of sinks exceeding sources by at least 50 Gg y-I. Given the uncertainties in process-specific surface flux estimates, we consider several distributions of terrestrial sources and sinks that satisfy the constraints on atmospheric abundance, Mole fractions corresponding to each distribution are simulated with a three-dimensional chemical transport model based on analyzed observed winds, coupled to a simple model of the ocean mixed layer. All of the resulting scenarios overestimate the observed zonal gradient, with interhemispheric ratios ranging from 1.39 to 1.60. In the absence of unknown sources, model results imply a biomass burning source near the upper limit of the range of present estimates (50 Gg y-1). Sensitivities to surface fluxes are also calculated to determine the extent to which uncertain terms in the methyl bromide budget can be better quantified using long-term measurements. Results show that a global network capable of accurately monitoring the monthly, zonal mean distribution of CH3Br would be able to distinguish between biomass burning fluxes and other known terrestrial sources and sinks. Modeled sensitivities to biomass burning emissions also highlight the importance of including tropical locations in any long-term monitoring network. However, technological sources and soil sinks have similar zonal patterns, and long-term, "background" mole fractions are relatively insensitive to zonal flux distributions. It is only when we examine the high frequency variability of the concentration that the effect of longitudinal gradients in the flux field becomes apparent. by Christopher D. Jensen. S.M. 2010-04-28T15:32:21Z 2010-04-28T15:32:21Z 1999 1999 Thesis http://hdl.handle.net/1721.1/54436 43876528 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 92 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Earth, Atmospheric, and Planetary Sciences. Jensen, Christopher D. (Christopher David), 1974- Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities |
| title | Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities |
| title_full | Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities |
| title_fullStr | Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities |
| title_full_unstemmed | Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities |
| title_short | Terrestrial sources and sinks of atmospheric methyl bromide : three-dimensional modeling of tropospheric abundance and sensitivities |
| title_sort | terrestrial sources and sinks of atmospheric methyl bromide three dimensional modeling of tropospheric abundance and sensitivities |
| topic | Earth, Atmospheric, and Planetary Sciences. |
| url | http://hdl.handle.net/1721.1/54436 |
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