Methane concentration in ice cores: A tool to reveal firn-ice properties and past climate changes ...
Polar ice sheets provide an archive of ancient air trapped in small air bubbles that can be analyzed directly for its composition. Deep ice core drillings in Antarctica and Greenland penetrated more than 3’000 m in the ice and provided mostly undisturbed concentration records of the greenhouse gases...
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| Format: | Thesis |
| Language: | unknown |
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:unas
2006
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| Online Access: | https://dx.doi.org/10.48350/192526 https://boris.unibe.ch/192526/ |
| Summary: | Polar ice sheets provide an archive of ancient air trapped in small air bubbles that can be analyzed directly for its composition. Deep ice core drillings in Antarctica and Greenland penetrated more than 3’000 m in the ice and provided mostly undisturbed concentration records of the greenhouse gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) in the past. Because these long lived trace gases are well mixed in the atmosphere, they reflect large-scale changes of at least hemispheric extent. In the frame of the European Project for Ice Coring in Antarctica (EPICA) two ice cores, providing currently the oldest greenhouse gas records, have been successfully drilled close to bedrock. This thesis includes a study, presenting records of atmospheric CH4 and N2O back to 650,000 years before present along the EPICA Dome C ice core. There is strong evidence that for this period the CH4 and N2O concentrations have never reached today’s values. Another investigation shows that the anthropogenic increases ... |
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