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| Titel |
Aircraft-borne DOAS limb observations of iodine monoxide around Borneo |
| VerfasserIn |
Katja Grossmann, Ryan Hossaini, Hannah Mantle, Martyn Chipperfield, Folkard Wittrock, Enno Peters, Johannes Lampel, Hannah Walker, Dwayne Heard, Gisèle Krystofiak, Valery Catoire, Marcel Dorf, Bodo Werner, Klaus Pfeilsticker |
| 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 |
250107807
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| Publikation (Nr.) |
 EGU/EGU2015-7521.pdf |
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| Zusammenfassung |
| Iodine monoxide (IO) has a major impact on the photochemistry of the troposphere. It can for
example catalytically destroy ozone, influence the atmospheric oxidation capacity by
changing the partitioning of the HOx and NOx species, or contribute to the formation of
ultrafine particles. Information regarding the vertical distribution of IO is still sparse since
only few vertical profiles of IO exist for the troposphere.
Spectroscopic measurements were carried out from aboard the research aircraft
DLR-Falcon during the SHIVA (Stratospheric ozone: Halogen Impacts in a Varying
Atmosphere) campaign at Malaysian Borneo in November and December 2011 to study the
abundance and transport of trace gases in the lower atmosphere. Sixteen research flights were
performed covering legs near the surface in the marine boundary layer (MBL) as
well as in the free troposphere (FT) up to an altitude of 13 km. The spectroscopic
measurements were evaluated using the Differential Optical Absorption Spectroscopy
(DOAS) technique in limb geometry, which supports observations of UV/visible
absorbing trace gases, such as O4, BrO, IO, NO2, HCHO, CHOCHO, HONO and
H2O, and altitude information was gained via the O4 scaling technique and/or full
inversion.
The inferred vertical profiles of IO showed mixing ratios of 0.5-1.5 ppt in the MBL,
which decreased to 0.1-0.3 ppt in the FT. Occasionally, the IO observed in the FT of the
marine environment coincided with elevated amounts of CO, but no IO was observed over
land, neither in the boundary layer, nor in the FT. This behavior strongly indicated that the
major sources for IO were organic and inorganic precursor molecules emitted from the ocean,
which during daytime rapidly formed a sizable amount of IO in the MBL that was
occasionally transported into the FT where efficient loss processes for IO must exist. The
inferred vertical profiles of IO are compared to simulations using the global 3-D chemistry
transport model TOMCAT including recent fluxes of HOI and I2 to examine possible sinks of
iodine. |
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