Diode Laser Hygrometer (DLH) IMPACTS

The Diode Laser Hygrometer (DLH) dataset is comprised of water vapor mixing ratio measurements as well as relative humidities (both concerning liquid water and ice) which are derived from the water vapor mixing ratio and ambient static temperature and pressure provided by the TAMMS instrument suite. These measurements were made using two separate DLH instruments installed on the NASA P-3B research aircraft, and the data from these instruments were combined to provide the best combination of accuracy, dynamic range, and data coverage. The two DLH instruments are (1) the zenith-mounted system which utilizes an optical path between the zenith port and the aircraft’s vertical tail, and (2) the short-path system, which utilizes an optical path between two fuselage-mounted fins. This dataset was measured during the 2023 campaign of the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) Earth Venture Suborbital 3 project. IMPACTS was a three-year sequence of winter season deployments conducted to study snowstorms over the U.S. Atlantic Coast (2020-2023). The project aimed to (1) Provide observations critical to understanding the mechanisms of snowband formation, organization, and evolution; (2) Examine how the microphysical characteristics and likely growth mechanisms of snow particles vary across snowbands; and (3) Improve snowfall remote sensing interpretation and modeling to advance prediction capabilities significantly. The DLH data files are available for flights from January 13, 2023, through February 28, 2023, and are in the ASCII format.

Diode激光湿度计（DLH）数据集由水蒸气混合比测量以及相对湿度（涉及液态水和冰的相对湿度）组成，这些数据均由TAMMS仪器套件提供的水蒸气混合比、环境静温和气压推导而来。这些测量使用了两台独立的DLH仪器进行，该仪器安装于NASA P-3B研究飞机上，并将这些仪器的数据合并，以提供最佳的结合精度、动态范围和数据覆盖。这两台DLH仪器分别为：（1）顶置系统，它利用了天顶端口与飞机垂直尾翼之间的光学路径；（2）短路径系统，它利用了机身安装的鳍之间的光学路径。该数据集是在2023年进行的“调查大西洋沿岸威胁性暴风雪的微物理和降水”（IMPACTS）地球探险亚轨道3项目活动中进行测量的。IMPACTS是一项为期三年的冬季部署序列（2020-2023），旨在研究美国大西洋沿岸的暴风雪。该项目旨在：（1）提供对理解雪带形成、组织和演化的机制至关重要的观测；（2）探讨雪粒微物理特性和可能的增长机制在雪带间的变化；（3）改进降雪遥感解释和建模，以显著提升预测能力。DLH数据文件可供2023年1月13日至2月28日的飞行数据使用，并以ASCII格式提供。