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| Titel |
Jovian Stratospheric Circulation: driven radiatively or mechanically? |
| VerfasserIn |
Xi Zhang, Run-Lie Shia, Adam Showman, Yuk Yung |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077051
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| Zusammenfassung |
| The existence of large-scale stratospheric circulation has been hypothesized since the 1990s
(e.g., Conrath et al. 1990; West et al. 1992). The evidences come from the recent observations
of stratospheric tracers such as hydrogen cyanide (HCN), carbon dioxide (CO2),
acetylene (C2H2) and ethane (C2H6) (Lellouch et al. 2006; Nixon et al. 2010).
Previous studies (e.g., Friedson et al. 1999; Liang et al. 2005) also proposed that
horizontal eddy mixing affects meridional transport processes. But the relative roles of
diffusion (eddy-mixing) and advection in the horizontal transport are highly uncertain
(Lellouch et al., 2006). On the other hand, whether the stratospheric circulation
on Jupiter is induced by differential heating or mechanical forcing from below
is still debated (e.g., Conrath et al., 1990; West et al., 1992), because the lower
stratosphere of Jupiter might not be purely radiatively controlled (Simon-Miller
et al., 2006; Zhang et al., 2012). In order to investigate the circulation pattern in
detail, we introduce a two-dimensional photochemical-diffusive-advective model to
simulate the distribution of stratospheric hydrocarbons. Analytical solutions are
derived to gain the physical insight of the coupled chemical-transport processes,
and validate the numerical methods (Zhang et al., 2013). The meridional transport
processes are constrained using the latitudinal distributions of C2H2 and C2H6 retrieved
from Cassini spacecraft measurements during Jupiter flyby in 2000 (Zhang et al.,
2012). The derived residual mean circulation pattern shows inconsistency with the
instantaneous zonally averaged radiative forcing map during the Cassini flyby (Zhang,
2012), implying that the lower stratospheric circulation might be partly mechanically
driven, as is the case for the Brewer-Dobson circulation on Earth. This research
was supported in part by NASA NNX09AB72G grant to the California Institute of
Technology. XZ was supported by the Bisgrove Fellowship in the University of Arizona. |
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