类地行星偏振特性研究

发布时间：2018-06-23 06:42

本文选题：地球 + 偏振　；参考：《中国科学院研究生院(云南天文台)》2015年硕士论文

【摘要】：本文首先介绍了偏振的相关概念、描述偏振的主要方法。然后我们介绍了行星偏振的研究现状以及目前对地球表面不同地表特征偏振研究所取得的主要结果,最后我们重点介讨论了地球作为一颗系外行星时的偏振特性。比较其它探测手段,行星的偏振探测能够为我们提供更多有关行星表面以及大气的细节信息,而地球的偏振测量则有助于我们寻找系外类地行星以及对其大气和表面特征的鉴定。在本文中,我们将地球看成为一颗与其寄主星(太阳)可分辨但其圆面不可分辨的行星来研究其在太阳照射后辐射进入太空的偏振特性。我们采用PARASOL的670nm (662.4nm～677.4nm)波段的观测结果,得到不同地表类型和云层的偏振度、反照率随散射角和方位角的变化,然后根据描述辐射偏振的Stokes参量可叠加特性,求得在特定散射角90°下,地球整体辐射的偏振度随白转的变化。结果发现,影响地球偏振的最大因素是海洋和云层,地球偏振度可以在18.6%-49%之问变化。由于气候变化导致的云层分布的随机性使得地球偏振度的变化具有快速多变的特点。这一特征可以帮助我们辨别系外类地行星。
[Abstract]:This paper first introduces the concept of polarization and describes the main methods of polarization. Then we introduce the research status of planetary polarization and the main results obtained from the research on the polarization of different surface characteristics of the earth's surface. Finally, we focus on discussing the polarization characteristics of the earth as an exoplanet. Compared with other means of exploration, planetary polarization detection can provide us with more details about the surface of the planet and its atmosphere. The polarization measurement of the earth will help us to identify the exoplanets and their atmospheric and surface characteristics. In this paper, we consider the earth as a planet which is distinguishable from its host star (the sun), but whose circular surface is indistinguishable, to study the polarization characteristics of its radiation into space after the sun is irradiated. Using the 670nm (662.4nm~677.4nm) band observations of Parasol, we obtain the variations of polarization, albedo with scattering angle and azimuth of different surface types and clouds, and then superposition the characteristics of Stokes parameters describing radiation polarization. The degree of polarization of the earth's global radiation varies with the white rotation at a specific scattering angle of 90 掳. The results show that the most important factors affecting the polarization of the earth are oceans and clouds, and the degree of polarization of the earth can vary by 18.6- 49%. Because of the randomness of the cloud distribution caused by climate change, the change of the degree of polarization of the earth is fast and changeable. This feature can help us identify exoplanets.
【学位授予单位】：中国科学院研究生院(云南天文台)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P185

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