Michael Mendillo

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A time-dependent one-dimensional model of Saturn’s ionosphere has been developed as an intermediate step towards a fully coupled Saturn-Thermosphere-Ionosphere-Model (STIM). A global circulation model (GCM) of the thermosphere provides the latitude and local time dependent neutral atmosphere, from which a globally varying ionosphere is calculated. Four ion(More)
We present an instrumentation plan for spectral imaging of MercuryÏs extended atmosphere. The approach depends upon simultaneous short-exposure images in white light and sodium, with the former used to select the frames for postintegration of the sodium images. The e†ects of atmospheric seeing are thus minimized by the combination of high-speed exposures(More)
[1] Ionospheric physics deals with the basic structure and variability of plasma within the upper atmospheres of the Earth and planets. Comparative studies foster both exploration and synthesis within diverse settings. In this paper we examine observations of the ionospheric profiles on Mars obtained on 9–27 March 1999 by the radio science experiment(More)
[1] We use a simple photochemical model of Mars’ ionosphere to investigate the changes in calculated electron density profiles, Ne(h), under the assumption that the only variable parameter is the solar irradiance. The period under study is 9–27 March 1999, corresponding to a series of Ne(h) observations made by the Mars Global Surveyor (MGS) Radio Science(More)
We present the first 3-dimensional self-consistent calculations of the response of Saturn’s thermosphere to diurnal solar heating, giving local time and latitudinal changes of temperatures, winds and composition at equinox and solstice. The large distance from the Sun combined with fast rotation of the planet and large heat capacities of the main(More)
We present three-dimensional numerical simulations for dynamics and energetics of Titan’s thermosphere. In so doing, we distinguish between the dynamics driven by solar insolation and those driven by vertical coupling to winds in Titan’s middle atmosphere. Our calculations reveal that the solar-driven thermospheric dynamics are characterized by the balance(More)
Optical diagnostic techniques have been applied to studies of equatorial aeronomy for nearly half a century. The use of scanning photometers and two-dimensional imagers to observe the spatial patterns associated with low-latitude emissions has been an increasingly used approach during the last few decades. In this paper we review the rationale for the use(More)
The problem of day-to-day variability in the occurrence of eo•mtorial spread F (ESF) ;.• dressed using multidiagnostic observations and semiempirical modeling. The observational resuits are derived from a two-night case study of ESF onset conditions observed at Kwajalein Atoll (Marshall Islands) using the ALTAIR incoherent scatter radar and all-sky optical(More)
[1] Using a time-dependent general circulation model of Titan’s thermosphere, we calculate the global distribution of neutral gases by winds and diffusion. Our calculations suggest that solar driven dynamics effectively redistribute constituents, causing considerable diurnal and seasonal changes in gas abundances. Subsidence causes an accumulation of(More)