Cloud Drop Size Distribution Measurement Using Phase Doppler Interferometry during Rain In Cumulus over the Ocean (RICO)

这个项目将使用一种新的仪器来测量海洋上信风积云中云滴的大小分布和浓度。该仪器基于相位多普勒干涉测量技术，将提供比通常在研究飞机上使用的仪器更好的尺寸分辨率和更稳定的校准。该项目是“海洋积云中的雨”（RICO）野外实验的一部分，该实验将收集2004年12月至2005年1月期间的测量数据。RICO的一个重要目标是了解“暖雨”过程，在此过程中雨是在没有冰相参与的情况下形成的。如果要实现这一目标，精确测量液滴大小分布是很重要的，因此这种新仪器的测量结果有望为RICO提供关键数据。要研究的具体课题包括“超大型”（50微米）气溶胶颗粒在雨形成中的重要性、环境空气夹带进入云中对云滴大小分布的影响，以及湍流引起的液滴之间碰撞率的可能提高。这些测量结果也应被其他RICO研究人员广泛用于他们自己对暖雨形成相关方面的研究。这项研究的一个重要的潜在影响将是为云物理的未来研究提供必要的测量技术。其他广泛的影响包括研究生在这一研究领域的培训，计划将代表性不足的少数民族和本科生纳入有关的教育活动，并为将成为RICO一部分的研究生研讨会系列作出贡献。

This project will use a new instrument to measure the size distribution and concentration of cloud droplets in trade-wind Cumulus clouds over the ocean. The instrument, based on the technique of phase-Doppler interferometry, will provide better size resolution and more stable calibration than instruments normally used on research aircraft. The project is part of the "Rain in Cumulus over the Ocean" (RICO) field experiment, which will collect measurements during December 2004 and January 2005. One important objective of RICO is to understand the "warm rain" process, in which rain is formed without involvement of the ice phase. Accurate measurement of the droplet size distribution is important if this objective is to be realized, so the measurements from this new instrument promise to provide key data for RICO. Specific topics to be investigated include the importance of "ultra-giant" (50 micrometer) aerosol particles in the formation of rain, the influence on the cloud droplet size distribution of entrainment of environmental air into the cloud, and the possible enhancement of collision rates among droplets caused by turbulence. The measurements should also be widely used by other RICO investigators in their own studies of related aspects of warm-rain formation. An important potential impact of this research will be the provision of a needed measurement technique for future studies in cloud physics. Other broad impacts include graduate student training in this area of research, planned inclusion of under-represented minorities and undergraduates in the related educational activities, and contributions to a graduate-student seminar series that will be part of RICO.