Recent changes in carbon monoxide mole fraction and stable isotope values observed in firn air from Summit, Greenland
Abstract
Carbon Monoxide (CO) is an important atmospheric trace gas that affects the oxidative capacity of the atmosphere and contributes indirectly to anthropogenic radiative forcing. Stable isotopes of CO (δ13CO and δC18O) serve as tracers that provide constraints for partitioning the sources of CO. Therefore, a good understanding of the past variations in CO mole fractions (xCO), δ13CO, and δC18O can help improve the skill of chemical transport models.
We present measurements of past atmospheric CO and CO stable isotopes from firn air at Summit, Greenland, which provides a record from approximately 1965 to 2011 CE. A firn gas transport model was used to simulate the transport of gases through the porous firn column, and an inverse model was used to reconstruct the firn air atmospheric histories of xCO, δ13CO and δC18O. Our results agree with previously published firn air records from Greenland: all three tracers show an increasing trend to a maximum in the late 1970s, followed by a negative trend through the end of the record. The negative trend in δ13CO and δC18O intensified in the last decade. We present an investigation into the cause of this continued decline using a mass balance approach and determine changes in CO source partitioning over time.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMC033...08P
- Keywords:
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- 3344 Paleoclimatology;
- ATMOSPHERIC PROCESSES;
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0724 Ice cores;
- CRYOSPHERE;
- 0726 Ice sheets;
- CRYOSPHERE