[P-PS04] Recent advances in the science of Venus

[PPS04-P12] 金星下層大気放射対流平衡構造の熱力学モデル依存性

*高橋 芳幸¹、林 祥介¹、はしもと じょーじ²、倉本 圭³、石渡 正樹³、樫村 博基¹ (1.神戸大学大学院理学研究科、2.岡山大学環境生命自然科学学域、3.北海道大学大学院理学研究院)

キーワード：金星、一次元放射対流平衡、非理想気体

The lower atmosphere of Venus is characterized by high pressure and high temperature, and is in a supercritical state of carbon dioxide. Because of that, the lower atmosphere of Venus cannot be treated as an ideal gas. However, the past numerical studies treated the Venusian atmosphere as the ideal gas. In addition, some of the circulation models have been assuming that the specific heat is constant. In this study, dependence of the radiative-convective equilibrium structure of the lower atmosphere of Venus on the specification of atmospheric thermodynamic model is investigated by the use of a one-dimensional radiative-convective equilibrium model and a series of thermodynamic models including ideal gases, van der Waals gases, and real gases. The one-dimensional radiative-convective equilibrium model utilized in this study solves energy equations of atmosphere and a uniform slab at the surface by the use of a radiative transfer model developed in our group and a series of above-mentioned thermodynamic models. The thermodynamic model of real gas is introduced by the use of the Helmholtz energy given by the EOS-CG mixture model. The radiative-convective equilibrium profiles obtained from the model have shown that the surface temperature for the atmosphere of real gas is different from that for the atmosphere of ideal gas with temperature-dependent specific heat by about 7 K. This difference is caused by the fact that the adiabatic lapse rate is different between the thermodynamic models of real gas and ideal gas. In the presentation, the factors affecting the adiabatic lapse rate and the effects of the use of constant specific heat in the model on the radiative-convective equilibrium structure will be discussed.