Cloud and Precipitation Studies Using a Millimeter Wavelength Doppler Radar

这项研究的目的是促进对云的发展和降水形成的理解，并提供可用于评估云中空气流动和混合过程的大涡模拟的观测结果。这项工作是基于地面遥感仪器的观测，这些仪器包括一个垂直指向的94 GHz（3.2毫米波长）雷达、一个超高频风廓线雷达和一个新建的垂直指向的x波段（3.2厘米波长）雷达。总之，这些雷达能够测量空气和云中的雨滴的垂直运动。可以确定液滴相对于空气的下落速度，从而可以估计液滴的大小分布。实验的主要地点是弗吉尼亚基的一个野外站，不过设备将被安装在一辆20英尺的拖车上，以便从其他地方进行观察。观测将用于记录晴天积云的结构，以及降水发展与产生大雨的云中的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学作出贡献，并通过提供验证数值模拟所需的数据对云模拟作出贡献。

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.