hsrl (01)

High-spectral-resolution lidar (HSRL) systems collect data about clouds and aerosols. These 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. Like 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. ARM 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）系统可采集云和气溶胶相关数据。该类系统能够提供光学厚度、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测量数据均以激光雷达廓线各点位处测得的分子散射作为参考基准，实现绝对定标。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可在无需预先假设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。退偏振观测结果还可实现冰云与水云的可靠区分。此外，所有测量数据均可计算得到严谨的误差估计值。极窄的视场角可抑制多次散射带来的干扰。小视场结合窄光学带宽，几乎可完全消除太阳散射光引入的噪声。ARM部署了两套HSRL系统，一套设于阿拉斯加北坡巴罗（North Slope of Alaska, NSA）观测站点，另一套搭载于第二代ARM移动观测平台（ARM Mobile Facility 2, AMF2），该平台会在野外试验期间部署于不同观测点位。