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| Titel |
Accelerator Mass Spectrometric determination of radiocarbon in stratospheric CO2, retrieved from AirCore sampling. |
| VerfasserIn |
Dipayan Paul, Henk A. Been, Huilin Chen, Rigel Kivi, Harro A. J. Meijer |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250109768
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| Publikation (Nr.) |
 EGU/EGU2015-9704.pdf |
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| Zusammenfassung |
| In this decade, understanding the impact of human activities on climate is one of
the key issues of discussion globally. The continuous rise in the concentration of
greenhouse gases, e.g., CO2, CH4, etc. in the atmosphere, predominantly due to
human activities, is alarming and requires continuous monitoring to understand the
dynamics. Radiocarbon is an important atmospheric tracer and one of the many used
in the understanding of the global carbon budget, which includes the greenhouse
gases like CO2 and CH4. Measurement of 14C (or radiocarbon) in atmospheric
CO2 generally requires collection of large air samples (few liters) from which CO2
is extracted and then the concentration of radiocarbon is determined. Currently,
Accelerator Mass Spectrometry (AMS) is the most precise, reliable and widely used
technique for atmospheric radiocarbon detection. However, the regular collection of air
samples from troposphere and stratosphere, for example using aircraft, is prohibitively
expensive.
AirCore is an innovative atmospheric sampling system, developed by NOAA. It
comprises of a long tube descending from a high altitude with one end open and the other
closed, and has been demonstrated to be a reliable, cost-effective sampling system for
high-altitude profile (up to ~ 30 km) measurements of CH4and CO2(Karion et al. 2010). In
Europe, AirCore measurements are being performed on a regular basis near Sodankylä since
September 2013. Here we describe the analysis of two such AirCore samples collected in
July 2014, Finland, for determining the 14C concentration in stratospheric CO2. The two
AirCore samples were collected on consecutive days. Each stratospheric AirCore
sample was divided into six fractions, each containing ~ 35 μg CO2 (~9.5 μg C).
Each fraction was separately trapped in 1 /4 inch coiled stainless steel tubing for
radiocarbon measurements. The procedure for CO2 extraction from the stratospheric air
samples; the sample preparation, with samples containing < 10 μg C, for AMS
measurements; and the resultant vertical profile of stratospheric 14CO2 will be described. |
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