Cloud and Precipitation Studies Using a Millimeter Wavelength Doppler Radar

这项研究的目的是促进对云发展和降水形成的了解，并提供可用于评估空气流动和云中混合过程的大涡模拟的观测结果。这项工作是基于使用地面遥感仪器进行的观测，该仪器包括一台垂直指向94 GHz(3.2毫米波长)的雷达、一台超高频风廓线雷达和一台新建的垂直指向X波段(3.2厘米波长)雷达。这些雷达结合在一起，能够测量云中空气和雨滴的垂直运动。可以确定液滴相对于空气的下落速度，从而能够估计液滴的尺寸分布。实验的主要地点是弗吉尼亚州基岛的一个野外空间站，尽管设备将安装在20英尺长的拖车上，以便从其他地点进行观测。观测将用来记录晴天积云的结构，以及降水发展和产生暴雨的云中垂直空气运动之间的关系。这项工作通过直接观测对降水物理作出了贡献，并通过提供验证数值模拟所需的数据对云模型作出了贡献。

The objectives of this research are to advance the understanding of cloud development and precipitation formation and to provide observations that can be used for evaluating large-eddy simulations of air flow and mixing processes in clouds. The work is based on observations using ground-based remote sensing instruments consisting of a vertically-pointing 94 GHz (3.2 mm wavelength) radar, a UHF wind-profiling radar, and a newly built vertically-pointing X-band (3.2 cm wavelength) radar. Together, these radars enable the measurement of vertical motions of both the air and the raindrops in clouds. The fall speed of the drops relative to the air can be determined, enabling the estimation of the drop-size distribution. The main site of the experiments is a field station at Virginia Key, although the equipment will be installed on a 20-ft trailer to enable observations from other locations. Observations will be used to document the structure of fair-weather cumulus clouds as well as the relations between precipitation development and vertical air motions in clouds producing heavy rain. The work contributes to precipitation physics by direct observation and to cloud modeling by providing the data needed for validating numerical simulations.