Stratospheric Circulation of Jupiter

Xi Zhang1,2

R. L. Shia2, A. P. Showman1, and Y. L. Yung2

1LPL, University of Arizona, United States2California Institute of Technology, United States

Supported by Bisgrove Postdoctoral Scholar Fellowship

Apr 11, 2013, Wien

Outline• Introduction • Derive the stratospheric circulation

based on Cassini and Voyager data• Problem and possible solutions

Based on Sieff et al. (1998)

?

Brower (1949), Dobson (1956), Figures from Seinfeld and Pandis (2006)

Jovian Stratosphere

Residual mean meridional circulation/Horizontal eddy mixing

Earth

How to derive the circulation pattern?

• Dynamical Simulation (requires wave properties)

• Diagnostic Approach (based on diabatic heating rate map)

Conrath et al. (1990); West et al. (1992); Moreno and Sedeno (1997)

• Tracer Approach (based on tracer distributions and 2-D chemical transport model)

Friedson et al. (1999); Liang et al. (2005); Lellouch et al. (2006)

Diagnostic Approach

Conrath et al. (1990)

West et al. (1992)

Radiatively Driven Mechanically Driven

Without Aerosol Heating With Aerosol Heating

Tracer Approach

Liang et al. (2005) Lellouch et al. (2006)

• Diffusional transport dominates, based on SL-9 dust data (Friedson et al., 1999) and C2H2 and C2H6 data (Liang et al., 2005)

• Horizontal advection is not negligible, based on SL-9 HCN and CO2 data (Lellouch et al., 2006)

This Study

Zhang et al. (2013a)

• Temperature and tracer maps from Cassini CIRS + Voyager IRIS spectra (Zhang et al., 2013a)• Global stratospheric aerosol map from Cassini ISS data (Zhang et al., 2013b)• Revisit both approaches

Zhang et al. (2013b)

~10 nm

Diagnostic ApproachWithout Aerosol Heating With Aerosol Heating

West et al. (1992)

This study:

Aerosol heating effect is significant

Tracer Approach• State-of-art Caltech/JPL 2-D chemical transport model, validated against analytical solutions (Zhang et al., 2013c)

• Residual circulation pattern derived, advection is not negligible.

Observation

Model with

Two patterns are not consistent

Diagnostic Approach Tracer Approach

• Uncertainties in the radiative diabatic heating rate ?• Atmosphere not in steady state?• Possible missing chemistry?

Test possible polar ethane source• Assume there is a strong ethane source (10 times

larger than the photochemical source) from ion-chemistry in the aurora region

Observation

Model with horizontal mixing

Summary• Residual mean meridional circulation pattern(s)

derived based on: (1) radiative diabatic heating rate map (2) tracer distributions and chemical transport model• Two patterns are not consistent • Possible solutions are discussed

Diagnostic Approach Tracer Approach