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| Titel |
Halocarbon measurements in the UTLS: results from the CARIBIC aircraft project |
| VerfasserIn |
David Oram, Johannes Laube, Adam Wisher, Debbie O'Sullivan, Tanja Schuck, Carl Brenninkmeijer |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053760
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| Zusammenfassung |
| The CARIBIC project aims to investigate the spatial and temporal distribution of a
wide-range of compounds in the UTLS region by making regular measurements from a
commercial airliner. Between 1998 and 2002 an instrumented freight container was flown on
a Boeing 767-ER aircraft operated by LTU International Airlines flying regularly
between Germany and destinations including the Maldives, southern Africa and
the Caribbean. Around 40 successful return flights were completed during this
initial 4-year period. The altitude range (up to 12 km) and flight routes allow for
sampling of mid-upper tropospheric air in tropical regions and lower stratospheric air in
mid-latitudes. The original instrument package included in-situ ozone, H2O, aerosol and CO
measurements, as well as a large volume whole air sampler (WAS), collecting 12
samples during the return flight. Compounds measured in WAS include hydrocarbons,
halocarbons and SF6, as well as the concentration and isotope ratios of CO, CO2,
CH4 and N2O. In December 2004, the flying programme recommenced with an
improved instrument package and a new aircraft/operator (Airbus 340/Lufthansa). New
instruments/measurements include NO/NOy, in situ CO2, PTRMS (oVOCs, CH3CN),
elemental mercury and DOAS (BrO, HCHO, etc). In addition, the WAS system
was upgraded to allow for the collection of 28 samples per flight. Recent flight
destinations include India, the Philippines, central America and southern Africa. The WAS
samples are analysed at UEA by GC-MS for approximately 40 halocarbons and
carbonyl sulphide (OCS). These measurements account for virtually 100% of organic
chlorine, bromine and iodine in the UTLS region. Since halocarbons are excellent
tracers of air mass origin (industrial pollution, biomass burning, stratospheric air,
oceanic air, etc), the data can be used to investigate the age and origin of air in the
tropopause region. Here we will give an overview of the CARIBIC halocarbon
measurements to date (geographical distributions, long-term trends, identification of
source regions, etc). Particular focus will be given to the measurements of very short
lived species (VSLS), such as CHBr3, CH2Br2 and CH3I, which are believed to
play an important, hitherto underestimated, role in stratospheric ozone chemistry. |
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