Rudimentary Considerations on the Dynamics of the Jovian Atmospheres

[摘要] The primary purpose of Part II of this two-part study is to offer a rationale to study the dynamics of the Jovian atmospheric layer (an upper part of the molecular fluid layer of the major planets, where the fluid can be treated as an ideal gas)based on a scale analysis.The results obtained are as follows:(1) The dynamics of the Jovian atmospheric layer can be described as almost two-dimensional flow under the geostrophic balance without strong vertical motions such as accompanying cumulus convection.Horizontal motions are purely determined by the conservation of potential temperature that does not include the vertical heat transport term.Consequently, the dynamics of the Jovian atmospheric layer is not appropriately described by the previously known geophysical fluid dynamic regimes (quasi-geostrophic, planetary-geostrophic, intermediate-geostrophic).We designate this dynamical regime as "thermo-geostrophic".(2) The cloud patterns in the Jovian atmospheres are not the resultants of cumulus convection, but rather they are mostly of long-enduring stratus-type clouds purely advected by horizontal motions. This is because the observed vertical heat flux from the interior is sufficiently explained by the slow vertical motions of large-scale nearly-geostrophic dynamics, in contrast to the Earth's atmosphere, where the cumulus convection activities are indispensable in this respect.

[学科分类] 大气科学