Improving Data Quality when Sampling Oxygen-18 Isotopes in Atmospheric Carbon Dioxide
Lumari Pardo, SOARS, UCAR, New York, NY
Plant respiration and photosynthesis are thought to influence the amount of oxygen-18 isotopes in atmospheric carbon dioxide, but water vapor trapped along with collected air samples affects the isotopic analysis process. If carbon dioxide exchanges Oxygen-18 isotopes with water vapor in the collection flasks, then it tends to reflect the isotopic signature of water instead of carbon dioxide. The problem is most significant in tropical and subtropical regions of the world. In this study, isotopic measurements since 1991 at two Bermuda sampling stations are compared with local meteorological data. This comparison could provide insight into the physical processes of biosphere-atmosphere interactions that may govern the measured oxygen isotopic signal. The two sampling stations on the same island offer a unique opportunity to test this hypothesis in a small region. Statistical analysis of over 360 measurements reveals that the percentage of samples rejected due to water vapor in sampling flasks is strongly correlated with specific humidity at the time of sample collection. Results from this research could significantly affect future sampling collection strategies and therefore improve the reliability of oxygen-18 measurements in carbon dioxide data in the Bermuda region. These results can enhance our understanding of interactions among meteorology, biology, environmental sciences, and could suggest that an alliance among them is needed.
Poster Session 1, Student Conference General Poster Session
Sunday, 20 January 2008, 5:30 PM-7:00 PM, Exhibit Hall B
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