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| Titel |
Stratospheric measurements of ozone-depleting substances and greenhouse gases using AirCores |
| VerfasserIn |
Johannes Laube, Emma Leedham Elvidge, Jan Kaiser, Bill Sturges, Pauli Heikkinen, Tuomas Laurila, Juha Hatakka, Rigel Kivi, Huilin Chen, Paul Fraser, Carina van der Veen, Thomas Röckmann |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250143943
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| Publikation (Nr.) |
 EGU/EGU2017-7715.pdf |
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| Zusammenfassung |
| Retrieving air samples from the stratosphere has previously required aircraft or large
balloons, both of which are expensive to operate. The novel “AirCore” technique (Karion et
al., 2010) enables stratospheric sampling using weather balloons, which is much more cost
effective. AirCores are long (up to 200 m) stainless steel tubes which are placed as a payload
on a small balloon, can ascend to over 30 km and fill upon descent, collecting a vertical
profile of the atmosphere. Retrieved volumes are much smaller though, which presents a
challenge for trace gas analysis. To date, only the more abundant trace gases such as carnon
dioxide (CO2) and methane (CH4) have been quantified in AirCores. Halogenated trace gases
are also important greenhouse gases and many also deplete stratospheric ozone. Their
concentrations are however much lower i.e. typically in the part per trillion (ppt) molar
range.
We here present the first stratospheric measurements of halocarbons in AirCores obtained
using UEA’s highly sensitive (detection limits of 0.01-0.1 ppt in 10 ml of air) gas
chromatography mass spectrometry system. The analysed air originates from a Stratospheric
Air Sub-sampler (Mrozek et al., 2016) which collects AirCore segments after the
non-destructive CO2 and CH4 analysis. Successfully measured species include CFC-11,
CFC-12, CFC-113, CFC-115, H-1211, H-1301, HCFC-22, HCFC-141b, HCFC-142b,
HCFC-133a, and sulphur hexafluoride (SF6). We compare the observed mixing ratios and
precisions with data obtained from samples collected during various high-altitude aircraft
campaigns between 2009 and 2016 as well as with southern hemisphere tropospheric
long-term trends. As part of the ERC-funded EXC3ITE (EXploring stratospheric
Composition, Chemistry and Circulation with Innovative Techniques) project more
than 40 AirCore flights are planned in the next 3 years with an expanded range
of up to 30 gases in order to explore seasonal and interannual variability in the
stratosphere.
References
Karion et al., J. Atmos. Ocean. Technol., 27(11), 1839–1853, 2010
Mrozek et al., Atmos. Meas. Tech., 9, 5607-5620, 2016 |
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