 |
| Titel |
Sulfur mono- and dioxides above Venus' clouds from SPICAV/SOIR solar occultations |
| VerfasserIn |
Denis Belyaev, Franck Montmessin, Jean-Loup Bertaux, Arnaud Mahieux, Anna Fedorova, Oleg Korablev, Emmanuel Marcq, Yuk Yung, Xi Zhang |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250047641
|
|
|
|
|
|
| Zusammenfassung |
| New measurements of sulfur dioxide (SO2) and monoxide (SO) in the atmosphere of Venus
by SPICAV/SOIR instrument onboard Venus Express orbiter provide powerful statistics
to study the behavior of gases above Venus’ clouds. The instrument (a set of 3
spectrometers) is capable to sound atmospheric structure above the clouds at several regimes
of observations (nadir, solar and stellar occultations) either in UV or in near IR
spectral ranges. We present results from solar occultations in the ranges of SO2
absorption (190-230 nm, 4 μm) and SO (190-230 nm). The dioxide was detected by
spectrometer SOIR at altitudes 65-80Â km in the IR and by spectrometer SPICAV at
85-105Â km in the UV. The monoxide’s absorption was measured only by SPICAV UV at
85-105Â km.
In the lower layer SO2 (65-80Â km) mixing ratio varies around 0.02-0.5Â ppmv, and in the
upper layer (85-105Â km) it increases with altitude from 0.05 to 2Â ppmv, while
[SO2]/[SO] ratio is around 1 to 5. The presence of the SOx abundance at high altitudes is
analyzed on the basis of H2SO4 photodissociation and temperature conditions in Venus
mesosphere. At levels 90-100Â km the content of sulfur dioxide was found to increase
with temperature from 0.1Â ppmv at 165-170Â K to 0.5-1Â ppmv at 190-192Â K. This
behavior confirms a concept about SO2 production in this altitude region by the
evaporation of H2SO4 from droplets and its subsequent photolysis around 100Â km. |
|
|
|
|
|
|