Major questions in planetary meteorology

Takeshi Imamura (ISAS/JAXA)

The major goals of planetary meteorology will be to explain a diversity of the

atmospheric general circulation of planets based on common principles of atmospheric

physics and to understand how an atmosphere responds to the changes of planetary

parameters and the solar flux. Such an understanding would also enable reproduction of

the evolutionary path of the Earth and the understanding of the climates of extrasolar

planets.

For the last several decades, problems of planetary-scale dynamics have been

extensively studied. The major problems include the super-rotation of Venus, dust

storms of Mars, multiple jets of Jupiter, etc. Now they are understood to some extent

with the aid of general circulation models of these planets; however, meso- and

micro-scale (subgrid) processes are empirically parameterized in those models. Because

of this limitation, cross-scale interaction, which is thought to be fundamental to the

achievement of an equilibrium state of the atmospheric structure, is not well understood.

Small-scale processes, such as convection in the planetary boundary layer, katabatic

winds, mountain waves, and internal gravity waves, are though to play key roles in

atmospheric dynamics and material transport. Moreover, the nature of such small-scale

processes and their interaction with planetary-scale dynamics needs to be understood for

the classical problems above.

The small-scale processes that needs extensive observations and modeling in the

coming decade will be: dust and water transport in the boundary layer of Mars, control

of the static stability of subsurface ice of Mars by boundary-layer processes, static

stability and the nature of convection near the Venus’ surface, angular momentum

exchange between the atmosphere and the solid planet of Venus, surface-atmosphere

chemical interaction on Venus, and energy and momentum transport by gravity waves

in the atmospheres of Venus, Mars and gas giants. Convection and convectively

generated waves in extreme environments, such as those in a runaway greenhouse

atmosphere, might also be an important topic. Comparative studies of those meso-scale

processes including the solar atmosphere will be valuable.

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Radio emissivity distribution correlated with topography

(Hashimoto & Abe, 2005

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