Harmel Tristan, Chami Malik
Université Pierre et Marie Curie, Laboratoire Océanographie de Villefranche, 06230 Villefranche sur Mer, France.
Opt Express. 2011 Oct 10;19(21):20960-83. doi: 10.1364/OE.19.020960.
An original atmospheric correction algorithm, so-called multi-directionality and POLarization-based Atmospheric Correction (POLAC), is described. This algorithm is based on the characteristics of the multidirectional and polarimetric data of the satellite PARASOL (CNES). POLAC algorithm is used to assess the influence of the polarimetric information in the visible bands on the retrieval of the aerosol properties and the water-leaving radiance over open ocean waters. This study points out that the use of the polarized signal significantly improves the aerosol type determination. The use of the polarized information at one visible wavelength only, namely 490 nm, allows providing estimates of the Angstrom exponent of aerosol optical depth with an uncertainty lower than 4%. Based on PARASOL observations, it is shown that the detection of the fine aerosols is improved when exploiting polarization data. The atmospheric component of the satellite signal is then better modeled, thus improving de facto the water-leaving radiance estimation.
本文描述了一种原始的大气校正算法，即所谓的基于多方向性和极化的大气校正（POLAC）算法。该算法基于卫星PARASOL（法国国家空间研究中心）多方向性和极化数据的特性。POLAC算法用于评估可见波段极化信息对开阔海洋上气溶胶特性反演以及离水辐射率的影响。本研究指出，极化信号的使用显著改善了气溶胶类型的判定。仅使用一个可见波长（即490纳米）的极化信息，就能提供气溶胶光学厚度埃斯特朗指数的估计值，其不确定性低于4%。基于PARASOL观测结果表明，利用极化数据时，细颗粒气溶胶的探测得到了改善。卫星信号的大气成分随后得到了更好的建模，从而实际上改善了离水辐射率的估计。
