The diurnal variation of polarization characteristics of the Earth treated as an exoplanet

• 来源期刊: 天文和天体物理学研究
• 年，卷（期）: 2019,（8）
• 页码范围: 113-120
• 页数: 8页
• 语种: 英文
• DOI: 10.1088/1674-4527/19/8/117

摘要

The diurnal polarization variation of the Earth,treated as an exoplanet with an unresolved disk but resolvable from its host star,is presented in three wavelength bands centered at 490 nm,670 nm and 865 nm respectively according to French satellite-borne PARASOL data.We aim to estimate disk-integrated polarization of the Earth with a phase angle of 55°.It is shown that:(1) the linear polarization signal and its variation are ascribed to the combination of surface feature distribution and atmospheric conditions acting as a variable polarimetric modulator;and (2) the polarimetric wavelength dependence is strong due to the atmospheric wavelength sensitivity.During the period when the PARASOL data were acquired,the cloud coverage ranged from 44.0％ to 57.7％,and the polarimetric diurnal variation amplitude was within 1.8％ in the 490nm band,1.3％ in the 670nm band and 1.5％ in the 865 nm band.