High Spectral Resolution Lidar - hsrl

High-spectral-resolution lidar (HSRL) systems collect data about clouds and aerosols. \n \nThese systems provide vertical profiles of optical depth, backscatter cross-section, depolarization, and backscatter phase function. All HSRL measurements are absolutely calibrated by reference to molecular scattering, which is measured at each point in the lidar profile. \n \nLike the Raman lidar, but unlike simple backscatter lidars such as the micropulse lidar, the HSRL can measure backscatter cross-sections and optical depths without prior assumptions about the scattering properties of the atmosphere. The depolarization observations also allow robust discrimination between ice and water clouds. In addition, rigorous error estimates can be computed for all measurements. A very narrow, angular field of view reduces multiple scattering contributions. The small field of view, coupled with a narrow optical bandwidth, nearly eliminates noise due to scattered sunlight. \n \nARM operates two HSRL systems, one at the Barrow, North Slope of Alaska (NSA) site and the other in the second ARM Mobile Facility (AMF2), which is deployed at various locations on field campaigns.

高光谱分辨率激光雷达（High-spectral-resolution lidar, HSRL）系统可收集云和气溶胶相关数据。

该类系统可提供光学厚度、后向散射截面、退偏振特性以及后向散射相位函数的垂直廓线。所有HSRL测量结果均以激光雷达廓线各点位处测得的分子散射为参照进行绝对定标。

与拉曼激光雷达类似，但不同于微脉冲激光雷达这类简易后向散射激光雷达，HSRL可在无需预先假定大气散射特性的前提下，直接测量后向散射截面与光学厚度。退偏振观测可实现冰云与水云的可靠区分。此外，可针对所有测量结果计算严谨的误差估计值。极窄的角视场可降低多次散射的影响。小视场配合窄光学带宽，几乎可完全消除太阳散射光引入的噪声。

大气辐射测量（Atmospheric Radiation Measurement, ARM）计划运行两套HSRL系统：一套设于阿拉斯加北坡巴罗（North Slope of Alaska, NSA）站点，另一套设于第二套ARM移动设施（ARM Mobile Facility, AMF2），该设施会在野外试验期间部署于多个不同地点。