The Numerical Simulation of Weather Modification By Cloud Seeding

9630008奥维尔，这项研究继续对云尺度和中尺度上的云播撒效应的数值模拟进行研究。这项工作是广泛的，处理高平原北部的层状地形云和冰雹。南达科他州矿业与技术学院(SDSM&Amp；T)已经开发出模拟云、雨、雪和冰雹发展的模型。已经发展了处理对流和层状云播撒的数值模拟的方法。播种剂的模拟包括播种剂的释放、播种剂在大气中的扩散以及播种剂与云中过冷液态水的相互作用。只是在过去的几年里，这些方法才被纳入完全三维的、依赖时间的模型中。这使得云播撒社区的许多假设第一次能够在最强大的科学框架中得到测试，尽管许多有用的见解和更多的理解是由较不动态的框架产生的。将对冬季/春季情况进行研究。此外，雷达模式气候学探测到的夏季对流模式导致的降水模式与冬季有很大不同。首席调查员也将模拟这些模式。这些夏季的云情况将允许测试模拟播撒对云团合并的影响，这是在以前的研究中在野外实验中检测到的重要影响。对冰雹的播撒进行了模拟，并揭示了有趣的结果。风暴是否有活跃的合并过程和细胞的寿命决定了对播种的反应程度。此外，播种材料的时机和放置对有效播种很重要。需要进一步的工作来加强理论基础。本文使用的模式模拟了降水冰粒谱的形成和发展过程。如果要就云播撒对冰雹的影响得出结论，这样的细节是必要的。首席调查人员还开发了模拟云中大气电过程的模型。将播撒作用对S暴雨影响的数值模拟应用于一次雷暴天气，分析其对暴雨起电的影响。这项研究的成功完成应有助于增进对降水产生和风暴带电所涉及的微物理过程的了解。

9630008 Orville This research continues ongoing investigations into the numerical simulation of cloud seeding effects on the cloud scale and mesoscale. The work is broad based, treating stratiform orographic clouds and hailstorms over the northern High Plains. Models have been developed at the South Dakota School of Mines and Technology (SDSM&T) that simulate the development of clouds, rain, snow, and hail. Methods have been developed that treat the numerical simulation of the seeding of convective and stratiform clouds. The simulation of the seeding agent involves the release of the agent, the spread of the seeding agent throughout the atmosphere, and the interaction of the seeding agent with the supercooled liquid water in the cloud. Only in the past few years have these methods been incorporated into fully three- dimensional, time-dependent models. This allows, for the first time, the many hypotheses of the cloud seeding community to be tested in the strongest scientific frameworks, although many useful insights and greater understanding have resulted from lesser dynamic frameworks. Studies of winter/spring situations will be carried out. In addition, the pattern of summer convection, as detected by radar pattern climatology leads to much different precipitation patterns than in the winter. The Principal Investigators also will simulate those patterns. These summertime cloud situations will allow testing of the effects of simulated seeding on the merging of cloud cells, an important effect detected in field experiments in previous research. The seeding of hailstorms has been simulated and is revealing intriguing results. Whether or not the storms have an active coalescence process and the lifetime of the cells determine the degree of response to the seeding. Also, the timing and the placement of the seeding material are important for the seeding to be effective. Further work is needed to strengthen the theoretical basis. The m odel being used for this work simulates the formation and development of the precipitating ice particle spectra. Such detail is necessary if conclusions are to be drawn concerning the effects of cloud seeding on hailstorms. The Principal Investigators also have developed models that simulate the processes of atmospheric electricity in clouds. The numerical simulations of seeding effects on the storm s microphysics will be applied to a vigorous thunderstorm and analyzed as to their effects on the storm electrification. Successful completion of this research should lead to increases in understanding of the microphysical processes involved in precipitation production and storm electrification.