Experimental and Numerical Investigations of Spectral Broadening and the Onset of Precipitation in Warm Rain In Cumulus over the Ocean (RICO) Cumuli

“海洋积云中的雨”实验将是对暖雨形成和信风积云的性质的多个研究人员的研究。该实验中正在研究的一个假设是，云中的湍流空气运动增加了云滴之间的碰撞速率，从而加速了雨的形成。这些研究人员将通过测量云中液滴位置的空间不均匀性来参与这项研究。使用这些测量，他们将评估这种不均匀导致降雨形成速度比没有湍流时更快的可能性。独一无二的仪器将包括一个新的“2D-S”(二维立体)成像探头，一个升级版的云粒子成像仪，它可以以高分辨率提供有关水流星空间分布的信息，以及一个以高分辨率测量遇到的每一滴水滴位置的仪器。这些仪器承诺为以前难以从飞机上测量的数量提供可靠的测量，包括毛毛雨大小范围和液滴聚集。如果它们被证明是可靠的，它们有可能对未来许多关于云中微物理过程的研究做出贡献。尤其是2D-S探测器，如果它提供了30-200微米液滴尺寸范围的良好文件，那么它可能对所有RICO调查人员的研究目标做出重大贡献，因为这对项目目标至关重要，用标准仪器测量很差。作为该项目的一部分，仪器的开发和测试也可能使未来的测量计划受益。未来几年的分析工作将包括与建模师合作，以符合观察到的特征的方式表示云中的微物理过程。

The "Rain in Cumulus over the Oceans" experiment will be a multi-investigator study of warm rain formation and the nature of trade wind Cumulus clouds. One hypothesis being investigated in that experiment is that turbulent air motions in clouds increase the collision rates among cloud droplets and so accelerate the formation of rain. These investigators will participate in that study by contributing measurements of the spatial inhomogeneities in droplet locations in the clouds. Using those measurements, they will evaluate the possibility that such inhomogeneities lead to faster rain formation than would be present without turbulence. Unique instruments will include a new "2D-S" (Two-Dimensional Stereo) imaging probe, an updated version of a cloud particle imager that can provide information on the spatial distribution of hydrometeors with fine resolution, and an instrument that measures the location of each droplet encountered with high resolution. These instruments promise to provide reliable measurements of quantities previously difficult to measure from aircraft, including the drizzle size range and the clustering of droplets. If they are shown to be reliable, they have the potential to contribute to many future studies of microphysical processes in clouds. The 2D-S probe in particular could make a major contribution to research objectives of all RICO investigators if it provides good documentation of the 30-200 micrometer droplet size range because this is of crucial importance to the project objectives and is poorly measured by standard instruments. The instrumentation development and testing that will occur as part of this project may benefit future measurement programs as well. Analysis efforts in subsequent years will include collaboration with modelers to represent microphysical processes in clouds in ways that are consistent with the observed characteristics.