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| Titel |
Solubility and solid state diffusion of Formaldehyde in Ice |
| VerfasserIn |
Manuel Barret, Stephan Houdier, Florent Dominé, Harry Beine, Petter Weibring, James Walega, Alan Fried, Dirk Richter |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250036613
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| Zusammenfassung |
| Formaldehyde (HCHO) is an oxidation intermediate of hydrocarbon oxidation and can
be an important source of oxidants (HOx) when photolysed. Gaseous HCHO is
exchanged between the snowpack and atmosphere. Processes involved include snowpack
(1) production from the photo-oxidation of organic matter, presumably present
as scavenged aerosol particles or (2) exchanges of HCHO dissolved within snow
crystals.
Testing the relative importance of both these processes is difficult in part because
we know neither the solubility of HCHO in ice as a function of partial pressure
of formaldehyde (PHCHO) and temperature, nor the diffusion rate of HCHO in
ice.
We have therefore studied the diffusion and solubility of HCHO in ice by exposing large
(8 cm) single crystals of ice to known PHCHO for several weeks. Experiments were
performed between -30Ë C and -7Ë C and allowed the construction of the phase diagram of
the solid solution of HCHO in ice. The diffusion coefficient was also measured and values are
in the range of 10-12 to 10-11 cm2.s-1.
Results from this experimental work will be compared to data obtained during the OASIS
2009 field campaign in Barrow where HCHO concentrations were measured both in snow
and atmosphere. |
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