Collaborative Research: An Airborne Radar Study of Cloud Structure and Composition

这笔赠款支持怀俄明大学的大气科学家和马萨诸塞大学阿默斯特大学的电气工程师继续合作，开发和改进95 GHz(3.2毫米波长)雷达，并将其应用于云和降水研究。该雷达通常用于怀俄明州国王航空研究飞机。与普通天气雷达不同，它的短波长提高了对小水滴的敏感度，使雷达能够探测到非降水云。它被称为怀俄明州云雷达，能够进行多普勒和偏振测量。它将于2001年7月临时安装在NCARC C-130研究飞机上，用于DYCOMS-II项目(海洋层积的动力学和化学)。这些数据将提供云顶附近混合区云结构的细节，还将表明细雨的存在，这被认为对海洋边界层的动力学有重要影响。WCR的能力将通过在King Air中增加第二个天线来扩展，这将允许双波束传输，以精细地观测对流云中的水平风场。这些想法将在高平原(科罗拉多州和怀俄明州)的一个实地项目中进行测试。主要研究内容如下：1.CCN个数与滴度、上升气流速度的关系。不同类型云的水平风场。积云中的夹带作用。海相层状云中的毛毛雨形成。改进了一种基于衰减的方法(“立体声”)来估计云中的水含量。结果与基础云物理、大气遥感和大尺度数值模式中云效应的参数化有关。

This grant supports a continuing collaboration between atmospheric scientists at the University of Wyoming and electrical engineers at the University of Massachusetts Amherst in the development and improvement of a 95 GHz (3.2 mm wavelength) radar and its application to studies of clouds and precipitation. The radar is ordinarily used in the Wyoming King Air research aircraft. Unlike ordinary weather radars, its short wavelength gives increased sensitivity to small drops and enables the radar to detect nonprecipitating clouds. Called the Wyoming Cloud Radar, it is capable of Doppler and polarimetric measurements. It will be mounted temporarily in the NCAR C-130 research aircraft for the DYCOMS-II project in July 2001 (Dynamics and Chemistry of Marine Stratocumulus). The data will give details on the cloud structure at the mixing region near cloud top and will also indicate the presence of drizzle, which is believed to have an important effect on the dynamics of the marine boundary layer. The capabilities of the WCR will be expanded by the addition of a second antenna in the King Air, which will permit dual-beam transmission for fine-scale observations of the horizontal wind field in convective clouds. The ideas will be tested in a field program in the High Plains (Colorado and Wyoming). The main research topics to be investigated are as follows:1. Relationships between CCN counts, drop concentration, and updraft speed.2. Horizontal wind field in different kinds of clouds.3. Entrainment in cumulus clouds.4. Drizzle formation in marine stratus clouds.5. Refinement of an attenuation-based method ("stereorad") for estimating cloud water content.Results are relevant to fundamental cloud physics, atmospheric remote sensing, and the parameterization of cloud effects in large-scale numerical models.