Measurements of the Charge, Size, and Type of Thunderstorm Precipitation Particles

[331 . 1749]马歇尔：这项研究的目的是看看降水中的电荷是否是雷暴中电力的主要原因。为此，研究人员建议分析1991年对流和降水/电气化实验（CaPE）期间在佛罗里达州10次雷暴中收集的降水颗粒的电荷、大小和二维形状的数据。这些数据尤其重要，因为测量温度范围为- 50至-20℃；这一地区还没有得到很好的研究，尽管有人认为风暴中的大部分电荷是在那里产生的。根据形状测量，提议者可以确定降水颗粒的类型：雨滴、雪花、冰雹或霰。然后，他们可以确定不同类型的粒子的极性和携带的电荷量。pi将与国家大气研究中心（NCAR）的同事合作，寻找温度、云中液态水含量、云粒子类型和数量、上升气流和下降气流、云中的位置等因素对粒子电荷的影响。他们将把滑翔机测量到的电场与测量到的粒子电荷所期望的电场进行比较；可比较的农田将表明，降水携带了风暴那部分的大部分电荷。pi将与NCAR的同事和其他CaPE研究人员合作，利用雷达数据将滑翔机轨迹叠加在反射率数据和多普勒雷达分析的风场上，从而将降水测量结果置于正确的风暴环境中。＊＊＊

9311749 Marshall The objective of this research is to see if the charge on precipitation is primarily responsible for the electricity in thunderstorms. Toward this end, the investigators propose to analyze data of the charge, size, and two-dimensional shape of precipitation particles collected inside ten Florida thunderstorms during the 1991 Convection and Precipitation/Electrification Experiment (CaPE). These data are especially important because of the measurements in the temperature range from -5o to -20oC; this region has not been well studied despite suggestions that much of the charge in storms is generated there. From the shape measurements the proposers can determine the type of precipitation particle: raindrop, snowflake, hailstone, or graupel. They can then determine the polarity and amount of charge carried on different types of particles. The PIs will collaborate with colleagues at the National Center of Atmospheric Research (NCAR) to look for influences on particle charges by temperature, cloud liquid water content, cloud particle types and numbers, updrafts and downdrafts, position in the cloud, etc. They will compare the electric fields measured by the sailplane to the electric field expected from the measured particle charges; comparable fields will suggest the precipitation carries most of the charge in that part of the storm. The PIs will collaborate with NCAR colleagues and other CaPE researchers using radar data to place the precipitation measurements in their correct storm context by superimposing sailplane tracks on reflectivity data and on wind fields from multiple Doppler radar analyses. ***