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K. Matcheva, P. Drossart, E. Raynaud, B. Sicardy, T. Widemann (DESPA, Paris Observatory)
The temperature profiles of the upper atmosphere of Jupiter derived from the Galileo probe in situ measurements and from ground based stellar occultations show strong evidence for atmospheric wave activity. The presence of gravity waves is also consistent with the system of sharp electron layers observed in the lower ionosphere during the Galileo radio occultations by Jupiter. Local in situ measurements and remote occultation techniques, however, do not allow for an unique determination of the horizontal parameters of the present waves, contain no information on the direction of wave propagation, and have a limited planetary coverage.
We consider the possibility of using Jupiter's H3+ near-IR emission as a complementary remote sensing method for studying the horizontal morphology of the wave activity in Jupiter's atmosphere at ionospheric heights. Similar to the gravity wave-driven variations in the OH nightglow in the Earth's atmosphere, the intensity of the jovian H3+ emission can be modified by a passing wave directly by inducing fluctuations in the ion temperature and number density, and indirectly by disturbing the local ion chemistry.
We perform numerical simulations of the response of the H3+ emission to propagating waves using a linear gravity wave model in a dissipative, nonisothermal atmosphere coupled with a detailed radiative transfer model of H3+ near-IR emission from an extended atmospheric region. We investigate the magnitude of the wave impact on the planetary emission for different values of the wave parameters in a variety of ionospheric conditions and for different H3+ profiles. Recent observations of the H3+ emission at high sensitivity with the VLT/ISAAC instrument at 3.5 micron in December 2000 allow us to determine an upper limit on the direct detection of gravity waves by this method.
This work is supported by the Marie Curie Fellowship Program of the European Community under contract HPMF-CT-2000-01005.
The author(s) of this abstract have provided an email address for comments about the abstract: Katia.Matcheva@obspm.fr