Quantifying mercury surface fluxes by combining atmospheric observations and models
Thesis: Ph. D. in Atmospheric Chemistry, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016. Cataloged from PDF version of thesis. Includes bibliographical references (pages 115-134). Mercury (Hg) is a critical environmental concern. Although an imp...
Main Author: | |
---|---|
Other Authors: | , |
Format: | Thesis |
Language: | English |
Published: |
Massachusetts Institute of Technology
2016
|
Subjects: | |
Online Access: | http://hdl.handle.net/1721.1/107107 |
id |
ftmit:oai:dspace.mit.edu:1721.1/107107 |
---|---|
record_format |
openpolar |
spelling |
ftmit:oai:dspace.mit.edu:1721.1/107107 2023-06-11T04:15:25+02:00 Quantifying mercury surface fluxes by combining atmospheric observations and models Song, Shaojie. Massachusetts Institute of Technology Noelle Eckley Selin. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences. 2016 134 pages application/pdf http://hdl.handle.net/1721.1/107107 eng eng Massachusetts Institute of Technology http://hdl.handle.net/1721.1/107107 971494816 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 Earth Atmospheric and Planetary Sciences Thesis 2016 ftmit 2023-05-29T08:23:51Z Thesis: Ph. D. in Atmospheric Chemistry, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016. Cataloged from PDF version of thesis. Includes bibliographical references (pages 115-134). Mercury (Hg) is a critical environmental concern. Although an important component of its biogeochemical cycle, large uncertainties still exist in the estimates of surface fluxes of mercury. Three projects presented in this thesis improve our understanding of mercury surface fluxes at different spatial scales by combining atmospheric observations and models. First, a global scale inverse model study uses observations at multiple ground-based stations and simulations from a three-dimensional chemical transport model (GEOS-Chem) to obtain a total mercury emission of about 5.8 Gg yr-¹, in which the ocean contributes about a half. The global terrestrial ecosystem is found to be neither a net source nor a net sink of Hg⁰ (gaseous elemental mercury). The optimized Asian anthropogenic emissions (0.7-1.8 Gg yr-¹) are very likely higher than bottom-up estimates, implying missing sources, higher activity levels, and/or lower control efficiencies in these inventories. Optimizing two physicochemical ocean parameters improves the model's ability in reproducing the seasonal pattern of observed Hg⁰. The inversion also suggests that the legacy mercury releases tend to reside in the terrestrial system rather than in the ocean. Second, the comparison of nested grid GEOS-Chem model simulations with aircraft observations support results from the global inversion, and further suggests that the Northwest Atlantic Ocean is a net source of Hg⁰, with high evasion fluxes in summer (related to the high precipitation rates and deposition fluxes of oxidized mercury), whereas the terrestrial ecosystem in the eastern United States is likely a net sink of Hg⁰ during summer. Third, a one-dimensional chemical transport model is built and used to simulate the mercury diurnal variabilities observed at Dome ... Thesis Northwest Atlantic DSpace@MIT (Massachusetts Institute of Technology) |
institution |
Open Polar |
collection |
DSpace@MIT (Massachusetts Institute of Technology) |
op_collection_id |
ftmit |
language |
English |
topic |
Earth Atmospheric and Planetary Sciences |
spellingShingle |
Earth Atmospheric and Planetary Sciences Song, Shaojie. Massachusetts Institute of Technology Quantifying mercury surface fluxes by combining atmospheric observations and models |
topic_facet |
Earth Atmospheric and Planetary Sciences |
description |
Thesis: Ph. D. in Atmospheric Chemistry, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2016. Cataloged from PDF version of thesis. Includes bibliographical references (pages 115-134). Mercury (Hg) is a critical environmental concern. Although an important component of its biogeochemical cycle, large uncertainties still exist in the estimates of surface fluxes of mercury. Three projects presented in this thesis improve our understanding of mercury surface fluxes at different spatial scales by combining atmospheric observations and models. First, a global scale inverse model study uses observations at multiple ground-based stations and simulations from a three-dimensional chemical transport model (GEOS-Chem) to obtain a total mercury emission of about 5.8 Gg yr-¹, in which the ocean contributes about a half. The global terrestrial ecosystem is found to be neither a net source nor a net sink of Hg⁰ (gaseous elemental mercury). The optimized Asian anthropogenic emissions (0.7-1.8 Gg yr-¹) are very likely higher than bottom-up estimates, implying missing sources, higher activity levels, and/or lower control efficiencies in these inventories. Optimizing two physicochemical ocean parameters improves the model's ability in reproducing the seasonal pattern of observed Hg⁰. The inversion also suggests that the legacy mercury releases tend to reside in the terrestrial system rather than in the ocean. Second, the comparison of nested grid GEOS-Chem model simulations with aircraft observations support results from the global inversion, and further suggests that the Northwest Atlantic Ocean is a net source of Hg⁰, with high evasion fluxes in summer (related to the high precipitation rates and deposition fluxes of oxidized mercury), whereas the terrestrial ecosystem in the eastern United States is likely a net sink of Hg⁰ during summer. Third, a one-dimensional chemical transport model is built and used to simulate the mercury diurnal variabilities observed at Dome ... |
author2 |
Noelle Eckley Selin. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences. |
format |
Thesis |
author |
Song, Shaojie. Massachusetts Institute of Technology |
author_facet |
Song, Shaojie. Massachusetts Institute of Technology |
author_sort |
Song, Shaojie. Massachusetts Institute of Technology |
title |
Quantifying mercury surface fluxes by combining atmospheric observations and models |
title_short |
Quantifying mercury surface fluxes by combining atmospheric observations and models |
title_full |
Quantifying mercury surface fluxes by combining atmospheric observations and models |
title_fullStr |
Quantifying mercury surface fluxes by combining atmospheric observations and models |
title_full_unstemmed |
Quantifying mercury surface fluxes by combining atmospheric observations and models |
title_sort |
quantifying mercury surface fluxes by combining atmospheric observations and models |
publisher |
Massachusetts Institute of Technology |
publishDate |
2016 |
url |
http://hdl.handle.net/1721.1/107107 |
genre |
Northwest Atlantic |
genre_facet |
Northwest Atlantic |
op_relation |
http://hdl.handle.net/1721.1/107107 971494816 |
op_rights |
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 |
_version_ |
1768372225824522240 |