Abstract. Validation of remote sensing retrievals of aerosol microphysical and optical properties requires in situ measurements of the same properties. We present here an improved imaging nephelometer for measuring the directionality and polarization of light (i.e. polarimetry) scattered at two wavelengths (405 nm and 660 nm) with high temporal resolution. The instrument was designed for airborne deployment and is capable of ground-based measurements as well. The Laser Imaging Nephelometer (LiNeph) uses two orthogonal detectors with wide-angle lenses and linearly polarized light sources to measure both the phase function, P₁₁(θ), and degree of linear polarization, -P₁₂/P₁₁(θ). In this work, we will describe the instrument function and calibration, as well as data acquisition and reduction. The instrument was first deployed aboard the NASA DC-8 during the 2019 FIREX-AQ campaign. Here, we present field measurements of smoke plumes that show that the LiNeph has sufficient resolution for 0.24 Hz polarimetric measurements at two wavelengths, 405 and 660 nm, at integrated scattering coefficients ranging from 50–80,000 Mm⁻¹.

中文翻译：

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用于飞机部署的激光成像浊度计

摘要。气溶胶微物理和光学特性的遥感反演验证需要对相同特性进行原位测量。我们在此提出了一种改进的成像浊度计，用于测量以高时间分辨率在两个波长（405 nm 和 660 nm）处散射的光（即偏振测量）的方向性和偏振。该仪器专为机载部署而设计，也能够进行地面测量。激光成像浊度计 (LiNeph) 使用两个带有广角镜头和线偏振光源的正交检测器来测量相位函数 P ₁₁ (θ) 和线偏振度 -P ₁₂ /P ₁₁(θ)。在这项工作中，我们将描述仪器功能和校准，以及数据采集和还原。该仪器在 2019 年 FIREX-AQ 活动期间首次部署在 NASA DC-8 上。在这里，我们展示了烟羽的现场测量结果，表明 LiNeph 在两个波长（405 和 660 nm）下具有足够的分辨率，可在 50–80,000 Mm ^{-1 的}综合散射系数下进行 0.24 Hz 偏振测量。