Student: Vincent Hue (currently Research Scientist at SwRI, San Antonio, TX, USA)
Title: “Modélisation physico-chimique 3D des atmosphères des planètes géantes”
Supervisors: M. Dobrijevic, F. Hersant, and T. Cavalié
Scientific Context: Long-term and spatially-resolved observations of the giant planets with Cassini and ALMA
Objective: Develop a 2D seasonal photochemical model of the giant planets to interpret the spatially-resolved observations
Results: The model solves the continuity equation for all altitudes (~H/3 resolution), latitudes (5° resolution) and as a funtion of time (10° heliocentric longitude resolution). The chemical network contains 22 species, 33 reactions and 24 photodissociations. The temporal evolution of the solar declination is computed from the orbital parameters (period, eccentricity, obliquity, etc.). The actiinic flux is computed with a 3Dspherical geometry radiative transfer model. The model can be fed with a seasonal altitude-latitude thermal field either coming from observations or simulated with a GCM ( general circulation model). The vertical and horizontal eddy mixing (Kyy and Kzz) and advective transport are implemented. Finally, the ring shadowing for Saturn is taken into account.
Acetylene and ethane in the stratosphere of Saturn, as a function of latitude. Comparison of model outputs with observations (taken from Hue et al. 2015).
Publications linked to the projet:
- Hue, V., Hersant, F., Cavalié, T., Dobrijevic, M., 2018. Photochemistry, mixing and transport in Jupiter’s stratosphere constrained by Cassini. Icarus 307, 106-123 .
- 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.