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| Titel |
Carbon Dioxide Ice Structure and Density in the Martian Mesosphere |
| VerfasserIn |
Thomas Mangan, Benjamin Murray |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123364
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| Publikation (Nr.) |
 EGU/EGU2016-2599.pdf |
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| Zusammenfassung |
| CO2 ice has been grown experimentally via deposition in order to mimic ice formation in
Martian mesospheric CO2 clouds. This is achieved through the use of a low temperature and
low pressure controlled stage mounted within an X-ray diffractomer (XRD). XRD patterns
of CO2 deposited at temperatures of 80 – 130 K and pressures below 1 mbar
were analysed using a Rietveld refinement method and fitted to a crystalline cubic
structure (space group Pa3). This crystal structure is consistent with XRD patterns also
taken of dry ice. CO2 ice densities were then determined from the refined lattice
parameters across the 80 – 130 K range and extrapolated using literature values
resulting in a temperature dependent density parameter valid over 80 – 195 K. This
temperature dependent parameter for CO2 ice density was applied to nucleation,
sedimentation and growth rates of CO2 ice particles under conditions relevant to the
Martian mesosphere. The results were then compared to commonly used literature
values, illustrating the need for the use of temperature dependent CO2 ice densities. |
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