类地行星偏振特性研究

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题名	类地行星偏振特性研究
作者	宋伟
学位类别	硕士
答辩日期	2015-07-01
授予单位	中国科学院研究生院
授予地点	北京
导师	屈中权
关键词	地球偏振反照率海洋沙漠积雪云层森林平原
其他题名	Study of Polarimetric Features of the Earth-like Exoplanet
学位专业	天体物理
中文摘要	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。
英文摘要	In this article, the concept of polarization is introduced and the polarization description is detailed as an introduction. Then we describe the present status of planet's polarimetry. The main results from the polarimetric study of the earth's surface features are given. Finally we focused on the polarization characteristics of the earth as an exoplanet. Compared with other probing techniques, the planetary polarimetry becomes more efficient to diagnose the details about the surface features of the exoplanet, and thus the polarimetry of our planet, the earth, is useful to search for the earth-like exoplanet. In this treatise, the earth is treated as a planet resolvable from its father star but its disk is unresolved. The data from polarimeter boarding French satellite PARASOL is used to get the polarimetric results of 5 surface features as well as clouds within the band 662.4nm~677.4nm. The results are expressed in the curves which reflect the variations of linear polarization degrees with the scattering angles and position angles respectively. Under the special case that the scattering angle is set to be 90 degrees, the polarization curves of the earth’s spin is obtained. It is found that the polarization degree is mainly influenced by the ocean as well as the cloud between 18.6% and 49%.And due to the rapid climate change on the earth, the polarization is altered correspondingly and rapidly. This character will help us to distinguish the earth-like exoplanet from other types of exoplanets.
语种	中文
学科主题	天文学
内容类型	学位论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/9457]
专题	云南天文台_光纤阵列太阳光学望远镜研究组
作者单位	中国科学院云南天文台
推荐引用方式 GB/T 7714	宋伟. 类地行星偏振特性研究[D]. 北京. 中国科学院研究生院. 2015.