Airborne Studies in the North Dakota Thunderstorm Project

冰雹是如何在深对流风暴中产生的，人们已经研究了好几年，但仍然存在许多问题。众所周知，冰雹是在被称为冰雹胚胎的小冰粒周围开始生长的。过去十年的结果引起了人们对暴风雨严重地区的关注，该地区被称为滋养细胞。这些是在主要风暴单体附近形成的小对流云，最终被吸收(“输送”)到主要对流单体中。据推测，至少在某些类型的冰雹中，这些滋养细胞是胚胎的主要生产者，最终会成长为大冰雹。美国国家科学基金会将与美国国家海洋和大气管理局一起参与一项研究冰雹的实地项目。这个项目被称为北达科他州雷雨项目，将在的夏天举行。作为这项研究工作的一部分，首席研究员打算研究胚胎生产的两个方面。首先，使用飞机现场测量，将研究饲养细胞的微物理特性。这将包括在饲养层细胞中进行人工冰核的实验播种，以研究过早成核对微物理过程的影响。第二个研究领域将集中在一种被称为精细尺度反射率图案的现象上。这些是雷达回波增强的区域，被认为是冰雹胚胎的来源。通过直接感应，校长计划调查这样的假设，即这些确实是胚胎高度集中的地区，这些胚胎经常进入风暴产生大冰雹的地区。//

How hail is produced in deep convective storms has been studied for several years, but many questions still remain. It is well-known that hailstones begin their growth around small ice particles which are referred to as hailstone embryos. Results over the last decade have drawn attention to an area in severe storms known as feeder cells. These are small convective clouds that form near the main storm cell and eventually are absorbed ("feed") into the main convective cell. It is speculated that, at least in some types of hailstorms, these feeder cells are the main producers of the embryos that eventually grow into large hail. In conjunction with the National Oceanic and Atmospheric Administration, the National Science Foundation will participate in a field program to study hailstorms. This project, known as the North Dakota Thunderstorm Project, will be held during the Summer of 1989. As part of this research effort, the Principal Investigator intends to study two aspects of embryo production. First, using in situ aircraft measurements, the microphysical characteristics of feeder cells will be investigated. This will include experimental seeding with artificial ice nuclei in the feeder cells to investigate the effects of premature nucleation on microphysical processes. The second area of investigation will focus on a phenomenon known as fine scale reflectivity patterns. These are areas of enhanced radar echo return and have been thought to be a source of hailstone embryos. Through direct sensing, the Principal plans to investigate the hypothesis that these are indeed areas of high concentration of embryos and that these embryos often find their way into the regions of the storm where large hail is produced. //