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| Titel |
Circulation of Venus upper mesosphere. |
| VerfasserIn |
Ludmila Zasova, Dmitry Gorinov, Alexey Shakun, Francesca Altieri, Alessandra Migliorini, Giuseppe Piccioni, Pierre Drossart |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098706
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| Publikation (Nr.) |
 EGU/EGU2014-14409.pdf |
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| Zusammenfassung |
| Observation of the O2 1.27 μm airglow intensity distribution on the night side of Venus is
one of the methods of study of the circulation in upper mesosphere 90-100 km.
VIRTIS-M on board Venus Express made these observations in nadir and limb modes
in Southern and Northern hemispheres respectively. Global map of the O2 night
glow is published (Piccioni et al. 2009). In this work we use for analysis only data,
obtained with exposure > 3 s to avoid high noisy data. It was found that intensity of
emission decreases to poles and to terminators (similar to Piccioni et al.2009) in
both hemispheres, which gives evidence for existence of SS-AS circulation with
transport of the air masses through poles and terminators with ascending/descending
flows at SS/AS areas. However, asymmetry of distribution of intensity of airglow is
observed in both hemispheres. Global map for southern hemisphere (from nadir
data) has good statistics at Ï > 10-20°S and pretty poor at low latitude. Maximum
emission is shifted from midnight by 1 – 2 hours to the evening (22-23h) and deep
minimum of emission is found at LT=2-4 h at Ï > 20°S. This asymmetry is
extended up to equatorial region, however statistic is poor there. No evident indication
for existence of the Retrograde Zonal Superrotation (RZS) is found: maximum
emission in this case, which is resulting from downwards flow, should be shifted to the
morning. The thermal tides, gravity waves are evidently influence on the night airglow
distribution. VIRTIS limb observations cover the low northern latitudes and they
are more sparse at higher latitudes. Intensity of airglow at Ï = 0 - 20° N shows
wide maximum, which is shifted by 1- 2 h from midnight to morning terminator.
This obviously indicates that observed O2 night glow distribution in low North
latitudes is explained by a superposition of SS-AS flow and RZS circulation at 95-100
km. This behavior is similar to the NO intensity distribution, obtained by SPICAV. |
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