Type
Text
Type
Dissertation
Date
2011-09-13
Keywords
atmospheric CO trends
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/71071
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Atmospheric carbon monoxide (CO) plays a significant role in atmospheric chemistry, as CO is a major sink for atmospheric hydroxyl radicals (OH) and thus strongly influences the oxidizing capacity of the atmosphere. In this thesis, new high precision measurements of atmospheric CO concentration and isotope composition during the past 700 years have been accomplished by analyzing the air in polar snow and ice. The first part of this study focuses on the trends of atmospheric CO over the past several decades. Firn air samples from the North Greenland Ice Core Project, Berkner iv Island, and North Greenland Eemian Ice Drilling (NEEM) have been analyzed to reconstruct atmospheric CO concentration and isotopic compositions during the past half century in both hemispheres. Firn diffusion models have been applied for NEEM firn air data to reconstruct past atmospheric trend in CO, indicating that the maximum of CO concentration and δ 18O in high latitude Northern Hemisphere occurred in 1970s-1980s, reflecting the largest contribution of CO emissions from fossil fuel combustion in this time. The second part of this study focuses on atmospheric CO records over the past 700 years. New decade-scale records of CO concentration as well as isotopic ratios have been produced from 40 Antarctic ice core samples (D47 and South Pole). CO concentration in the 13th century was ~50 ppbv, which is comparable with today’s CO level in high-latitude Southern Hemisphere. CO level then gradually dropped to 38 ppbv during the following 300 years, followed by a gradual increase to 55 ppbv in 1900. δ13C and δ18O decreased by about 3‰ and 5‰ respectively from 1380 to 1700, then increased by about 3‰ and 5‰ respectively by 1900. Mass balance model implies biomass burning emissions were high in the 13th century, but reduced by ~50% over the next 300 years and then almost doubled by 1900. We conclude biomass burning strongly modulated the CO budget during preindustrial time and considerably decreased since the early 20th century. This decrease was nearly compensated by the concomitant CH4 increase, bringing back CO mixing ratio close to its maximum level observed over the last 700 years.
Recommended Citation
Wang, Zhihui, "Records of δ13C, δ18O and Concentration of Atmospheric CO In The Past" (2011). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 278.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/278