Ozone chemistry during global glaciations : a possible climate feedback
Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2018
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| Online Access: | http://hdl.handle.net/1721.1/114119 |
| _version_ | 1811076585638330368 |
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| author | Hsiang, Solomon M |
| author2 | R. Alan Plumb. |
| author_facet | R. Alan Plumb. Hsiang, Solomon M |
| author_sort | Hsiang, Solomon M |
| collection | MIT |
| description | Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006. |
| first_indexed | 2024-09-23T10:24:28Z |
| format | Thesis |
| id | mit-1721.1/114119 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T10:24:28Z |
| publishDate | 2018 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1141192019-04-11T08:41:26Z Ozone chemistry during global glaciations : a possible climate feedback Hsiang, Solomon M R. Alan Plumb. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences. Earth, Atmospheric, and Planetary Sciences. Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006. Cataloged from PDF version of thesis. Pages 77-78 missing from original thesis. Includes bibliographical references (pages 76-84). A theory for changes in ozone chemistry during late Proterozoic global glaciations is developed. The possible significance of temperature, humidity, nitrogen oxides, reactive chlorine, lightning frequency, surface deposition and albedo as altered constraints on ozone processes is discussed. An elementary box model is developed by the author to make first order judgments regarding the significance of chemistry changes on ozone concentrations and its climactic effect. A one dimensional photochemical-transport model (Kasting, 1995) was used to more precisely determine the effects of global glaciations on ozone concentrations up to 5 hPa in several latitude bands. Reduced NO₂ availability in the stratosphere seems to dominate ozone's response (positive anomalies) in the stratosphere. Low temperatures, low humidity, reduced lighting frequency and altered chlorine and nitrogen chemistry collectively reduce ozone presence in the troposphere, however the overall sign of the tropospheric ozone anomaly depends heavily on poorly characterized deposition rates. With output from the one-dimensional photochemistry model, a time-varying ozone concentration field was assembled for the entire planet and used in snowball runs of the General Circulation Model (NCAR Community Atmosphere Model 3.0). These runs were compared to a controlled snowball run with a modern ozone field to discern the climactic significance of altered ozone. Results suggest that ozone concentrations during global glaciations might directly produce global average surface radiation anomalies of -1.5 ~ 1.5 W/m² , resulting in global average surface temperature anomalies of -0.5 ~ 0.5°K. Magnitude and sign uncertainties result from poorly known deposition rates for ozone over frozen surfaces and the simplicity of the modeling technique. The indirect effect of increasing stratospheric ozone, i.e. a reduction in atmospheric oxidative capacity, may result in positive anomalies of other green house gasses and is discussed as an area for further research. by Solomon M. Hsiang. S.B. 2018-03-12T19:30:41Z 2018-03-12T19:30:41Z 2006 2006 Thesis http://hdl.handle.net/1721.1/114119 1027706808 eng MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 84 pages application/pdf Massachusetts Institute of Technology |
| spellingShingle | Earth, Atmospheric, and Planetary Sciences. Hsiang, Solomon M Ozone chemistry during global glaciations : a possible climate feedback |
| title | Ozone chemistry during global glaciations : a possible climate feedback |
| title_full | Ozone chemistry during global glaciations : a possible climate feedback |
| title_fullStr | Ozone chemistry during global glaciations : a possible climate feedback |
| title_full_unstemmed | Ozone chemistry during global glaciations : a possible climate feedback |
| title_short | Ozone chemistry during global glaciations : a possible climate feedback |
| title_sort | ozone chemistry during global glaciations a possible climate feedback |
| topic | Earth, Atmospheric, and Planetary Sciences. |
| url | http://hdl.handle.net/1721.1/114119 |
| work_keys_str_mv | AT hsiangsolomonm ozonechemistryduringglobalglaciationsapossibleclimatefeedback |