Boesche Eyk, Stammes Piet, Ruhtz Thomas, Preusker Réne, Fischer Juergen
Institute for Space Sciences, Free University Berlin, Berlin, Germany.
Appl Opt. 2006 Dec 1;45(34):8790-805. doi: 10.1364/ao.45.008790.
We analyze the sensitivity of the degree of linear polarization in the Sun's principal plane as a function of aerosol microphysical parameters: the real and imaginary parts of the refractive index, the median radius and geometric standard deviation of the bimodal size distribution (both fine and coarse modes), and the relative number weight of the fine mode at a wavelength of 675 nm. We use Mie theory for single-scattering simulations and the doubling-adding method with the inclusion of polarization for multiple scattering. It is shown that the behavior of the degree of linear polarization is highly sensitive to both the small mode of the bimodal size distribution and the real part of the refractive index of aerosols, as well as to the aerosol optical thickness; whereas not all parameters influence the polarization equally. A classification of the importance of the input parameters is given. This sensitivity study is applied to an analysis of ground-based polarization measurements. For the passive remote sensing of microphysical and optical properties of aerosols, a ground-based spectral polarization measuring system was built, which aims to measure the Stokes parameters I, Q, and U in the visible (from 410 to 789 nm) and near-infrared (from 674 to 995 nm) spectral range with a spectral resolution of 7 nm in the visible and 2.4 nm in the near infrared. We compare polarization measurements taken with radiative transfer simulations under both clear- and hazy-sky conditions in an urban area (Cabauw, The Netherlands, 51.58 degrees N, 4.56 degrees E). Conclusions about the microphysical properties of aerosol are drawn from the comparison.
我们分析了太阳主平面内线性偏振度随气溶胶微物理参数的变化敏感度，这些参数包括：折射率的实部和虚部、双峰粒径分布（细模态和粗模态）的中位半径和几何标准差，以及在675nm波长下细模态的相对数量权重。我们使用米氏理论进行单次散射模拟，并采用包含偏振的加倍-相加法进行多次散射模拟。结果表明，线性偏振度的行为对双峰粒径分布的小模态、气溶胶折射率的实部以及气溶胶光学厚度都高度敏感；然而，并非所有参数对偏振的影响都是等同的。我们给出了输入参数重要性的分类。该敏感度研究被应用于地面偏振测量分析。为了对气溶胶的微物理和光学特性进行被动遥感，我们搭建了一个地面光谱偏振测量系统，其目的是在可见光（410至789nm）和近红外（674至995nm）光谱范围内测量斯托克斯参数I、Q和U，其中可见光的光谱分辨率为7nm，近红外的光谱分辨率为2.4nm。我们在城市地区（荷兰卡堡，北纬51.58度，东经4.56度）的晴空和雾霾天气条件下，将偏振测量结果与辐射传输模拟结果进行了比较。通过比较得出了关于气溶胶微物理特性的结论。
