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arXiv 1209.1833astro-ph.EP
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行星大气的一个解析辐射-对流模式

An Analytic Radiative-Convective Model for Planetary Atmospheres

Tyler D. Robinson, David C. Catling

摘要:

本文提出了一个解析的行星大气热结构的一维辐射-对流模式。我们的模型假设热辐射转移是灰色的,可以表示为双流近似。模型大气被假定为流体静力平衡,与大气压力和灰色热光学深度之间的幂律缩放。我们的模型的对流部分采取以下考虑冷凝的挥发物通过一个缩放参数的干燥的蒸发器的蒸发器。通过结合这些假设,我们产生简单的,解析表达式,允许计算的大气压力-温度分布,以及热辐射通量和对流通量的分布的表达式。我们探索我们的模型的一般行为。这些研究包括:(1)太阳光大气衰减较弱的世界,我们发现这些世界往往具有相对较高的辐射对流边界;(2)太阳光在整个大气中有一定衰减的世界,我们发现这些世界可以产生浅或深的辐射对流边界,这取决于太阳光衰减的强度;以及(3)强烈辐照的巨行星(包括热对流层),在那里我们探索的条件下,这些世界获得分离的对流区在其对流层中部。最后,我们验证我们的模型,并通过比较金星,木星和泰坦的平均观测到的热结构,并通过比较计算的通量分布更复杂的模型,证明其实用性。

英文摘要:

We present an analytic 1-D radiative-convective model of the thermal structure of planetary atmospheres. Our model assumes that thermal radiative transfer is gray and can be represented by the two-stream approximation. Model atmospheres are assumed to be in hydrostatic equilibrium, with a power law scaling between the atmospheric pressure and the gray thermal optical depth. The convective portions of our models are taken to follow adiabats that account for condensation of volatiles through a scaling parameter to the dry adiabat. By combining these assumptions, we produce simple, analytic expressions that allow calculations of the atmospheric pressure-temperature profile, as well as expressions for the profiles of thermal radiative flux and convective flux. We explore the general behaviors of our model. These investigations encompass (1) worlds where atmospheric attenuation of sunlight is weak, which we show tend to have relatively high radiative-convective boundaries, (2) worlds with some attenuation of sunlight throughout the atmosphere, which we show can produce either shallow or deep radiative-convective boundaries, depending on the strength of sunlight attenuation, and (3) strongly irradiated giant planets (including Hot Jupiters), where we explore the conditions under which these worlds acquire detached convective regions in their mid-tropospheres. Finally, we validate our model and demonstrate its utility through comparisons to the average observed thermal structure of Venus, Jupiter, and Titan, and by comparing computed flux profiles to more complex models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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