PhD thesis supervision

Completed PhD thesis

PhD student: V. Hue (now Research Scientist at SwRI in San Antonio, USA)

Thesis title: “Modélisation physico-chimique 3D des atmosphères des planètes géantes”

Year: 2012-2015

Supervision: M. Dobrijevic, F. Hersant, and T. Cavalié

Scientific context: Cassini and ALMA spatially-resolved observations of giant planets

Goal: Develop a 2D seasonal photochemical model for giant planet atmospheres in order to interpret spatially resolved observations.

Results: The model solves the continuity equation for altitudes (resolution ~H/3), latitudes (resolution of 5°), and as a function of time (resolution of 10° in heliocentric longitude), using spherical geometry. The chemical network includes 22 species, 33 reactions and 24 photodissociations. The temporal evolution of the local solar declination is computed from the orbital parameters (e.g., period, eccentricity, obliquity). The actinic flux is computed with a full-3D spherical radiative transfer model. The model can be fed with a seasonal and latitude-altitude thermal field directly simulated by a GCM or retrieved from observations. Vertical and meridional eddy diffusion (Kzz and Kyy) and advective transport are implemented. Ring shadowing effects are included for Saturn.

Acetylene and ethane in the stratosphere of Saturn, as a function of latitude. Observation-model comparison (taken from Hue et al. 2015).

 

Related publications:

  • Hue, V., Hersant, F., Cavalié, T., Dobrijevic, M., 2018. Photochemistry, mixing and transport in Jupiter’s stratosphere constrained by Cassini. Icarus, accepté.
  • Hue, V., Greathouse, T. K., Cavalié, T., Dobrijevic, M., Hersant, F., 2016. 2D photochemical modeling of Saturn’s stratosphere. Part II: Feedback between composition and temperature. Icarus 267, 334-343.
  • Hue, V., Cavalié, T., Dobrijevic, M., Hersant, F., Greathouse, T. K., 2015. 2D photochemical modelling of Saturn’s stratosphere. Part I: Seasonal variation of atmospheric composition. Icarus 257, 163-184.
  • Cavalié, T., Dobrijevic, M, Fletcher, L. N., Loison, J. C., Hickson, K. M., Hue, V., Hartogh, P., 2015. The photochemical response to the variation of temperature in Saturn’s 2011-2012 stratospheric vortex. Astronomy and Astrophysics 580, A55.
  • Dobrijevic, M., Cavalié, T., Billebaud, F., 2011. A methodology to construct a reduced chemical scheme for 2D-3D photochemical models: Application to Saturn. Icarus 214, 275-285.

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