We report on the development of a novel multi-spectral polarimetric imager for atmospheric remote sensing of aerosol and cloud properties. The instrument concept, called the Aerosol Limb Imager (ALI), is ultimately intended for satellite measurements from a low Earth orbit. It utilizes a coupling of a dual transducer acousto-optic tunable filter and a liquid crystal rotator to provide dual linear polarization observations over a wide spectral range covering 600 nm-1500 nm. In the limb, or side-viewing, geometry, these measurements provide the capability to resolve vertical and horizontal distributions of aerosol and cloud properties such as extinction coefficient, optical depth, and particle distribution parameters. Here, we present the design and performance of an ALI prototype. Lab characterization of the instrument is used to develop a mathematical instrument model to predict signal levels under various atmospheric conditions. Results from a sub-orbital flight of the ALI prototype on a stabilized high-altitude stratospheric balloon gondola are presented that show the first known polarimetric, multi-spectral images of the limb radiance. The signal levels obtained agree reasonably well with those predicted by the instrument model using radiative transfer calculations for typical atmospheric conditions.

中文翻译：

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用于气溶胶和薄云大气廓线的多光谱偏振成像仪：原型设计和亚轨道性能

我们报告了一种用于气溶胶和云特性的大气遥感的新型多光谱偏振成像仪的开发。该仪器概念称为气溶胶肢体成像仪 (ALI)，最终用于低地球轨道的卫星测量。它利用双换能器声光可调滤波器和液晶旋转器的耦合，在覆盖 600 nm-1500 nm 的宽光谱范围内提供双线性偏振观测。在肢体或侧视几何中，这些测量提供了解析气溶胶和云特性的垂直和水平分布的能力，例如消光系数、光学深度和粒子分布参数。在这里，我们介绍了 ALI 原型的设计和性能。仪器的实验室表征用于开发数学仪器模型，以预测各种大气条件下的信号电平。展示了 ALI 原型在稳定的高空平流层气球吊舱上的亚轨道飞行结果，显示了第一个已知的肢体辐射的偏振多光谱图像。获得的信号电平与仪器模型使用典型大气条件的辐射传输计算所预测的信号电平相当吻合。