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  • The Venus Global Ionosphere-Thermosphere Model (V-GITM): A Coupled Thermosphere and Ionosphere Formulation

    work
    Creator:
    Ponder, Brandon M., Ridley, Aaron J., Bougher, Stephen W., Pawlowski, David, and Brecht, Amanda
    Description:
    This research was completed to introduce a state-of-the-art Venus GCM to the modeling community. Validation studies were performed to give credence to the model's results. and This data set is made available under a Creative Commons Public Domain license (CC0 1.0). The python scripts contained were ran on macOS Monterey version 12.7 with Python 3.9. Numpy version: 1.19.4 Pandas version: 1.2.0
    Keyword:
    Venus, GITM, Ionosphere, Thermosphere, Solar minimum, Navier-stokes, Fluid dynamics, Shocks, V-GITM, and VGITM
    Citation to related publication:
    Ponder, Brandon & Ridley, Aaron J. & Bougher, Stephen W. & Pawlowski, D. & Brecht, A. (2023). The Venus Global Ionosphere-Thermosphere Model (V-GITM): A Coupled Thermosphere and Ionosphere Formulation. JGR Planets. In Press.
    Discipline:
    Science

  • A 3D Physics-based Particle Model of the Venus Oxygen Corona: Variations with Solar Activity

    work
    Creator:
    Valeriy Tenishev
    Description:
    Here we present an investigation of the variability of Venus' extended oxygen corona. For that, we employ a combination of a fluid model VTGCM for simulating Venus' ionosphere and thermosphere and kinetic model AMPS. We have found excellent agreement of the model results with PVO observations of the corona when the modeling is done assuming the solar maximum conditions, which corresponds to the solar conditions during the observations. We also found that the oxygen density strongly depends on the solar conditions and varies by order of magnitude over a solar cycle. That explains why the extended oxygen corona was observed only at the solar maximum. The result presented in this paper will be used in a later study of the planet's interaction with the ambient solar wind, where the corona model defines the mass loading coefficient.
    Keyword:
    Venus, VTGCM, AMPS, and Venus extended corona
    Discipline:
    Science

  • Planetary-scale Wave Impacts on the Venusian Upper Mesosphere and Lower Thermosphere: Supporting Datasets for VTGCM Numerical Simulations

    work
    Creator:
    Bougher, S. W. (University of Michigan) and Brecht, A. S. (NASA Ames Research Center)
    Description:
    This work examines the planetary wave-induced variability within the upper mesosphere/lower thermosphere of Venus by utilizing the Venus Thermospheric General Circulation Model (VTGCM). Rossby and Kelvin wave perturbations are driven by variations in the geopotential height of the VTGCM lower boundary (~70 km). A suite of simulations was conducted to examine the impact of the individual and combined waves propagating from two different lower boundary conditions (uniform and varying). The Kelvin wave is the more dominant wave which produces the most variability, as was shown in Hoshino et al., 2012. The combination of the Kelvin and Rossby waves provides a maximum temperature amplitude of 13 K at 92 km and maximum zonal wind amplitude of 23 m/s at 102 km. The combined waves overall are able to propagate up to 125 km. Most of the variation within the temperature, winds, and composition occurs between 70 km and 110 km. The varying lower boundary increases the magnitude of the wave deposition but weakly changes the propagation altitude. The thermal variation due to the planetary waves does not reproduce most observed variations. The simulated O2 IR nightglow emission is sensitive to the waves with respect to intensity and local time, but lacks latitudinal variation. The integrated intensity ranges from 1.2 MR to 1.65 MR and the local time ranges from 0.33 local time to 23.6 local time. Overall, planetary waves do affect the atmospheric structure, but there are still observed large variations that planetary waves alone cannot explain (i.e. thermal structure).
    Keyword:
    Venus, planetary waves, upper mesophere, lower thermosphere, and O2 nightglow
    Citation to related publication:
    Brecht, A. S., Bougher, S. W., Shields, D., & Liu, H.-L. (2021). Planetary-scale wave impacts on the Venusian upper mesosphere and lower thermosphere. Journal of Geophysical Research: Planets, 126, e2020JE006587.  https://doi.org/10.1029/2020JE006587
    Discipline:
    Science