Mesoscale Structures and Dynamics of Mid-Latitude Cyclones

中纬度地区的9632580个霍布斯气旋影响了世界大片地区。因此，改进对与中纬度气旋有关的天气的理解和预报一直是20世纪气象学的主要目标之一。尽管在大(天气)尺度上预报温带气旋的基本认识和能力方面取得了非常重大的进展，但在预报与这些系统有关的当地降水和恶劣天气方面的进展要慢得多。这归因于对对流尺度(约0.1-10公里)和中尺度(约10-1000公里)上的过程和现象认识不足。在过去20年左右的时间里，华盛顿大学的云物理研究小组一直在研究温带气旋，重点放在降水的微物理和中尺度方面。这些研究导致了对美国西海岸雨带的分类和研究，以及对美国东海岸和美国中部气旋的研究。后两项研究为落基山脉背风区产生的气旋提出了一个新的概念模型，并确定了可能在美国中部造成恶劣天气的两个大范围雨带。本研究是这些研究的延伸。将进行三个主要领域的研究。一是对美国中部新的气旋概念模式进行进一步评估，以改善其观测和理论基础，并增加其作为天气预报辅助工具的效用。第二项任务是调查形成狭窄冷锋雨带的机制，这是温带气旋的普遍特征，可以产生恶劣的当地天气。气旋的另一个共同特征，即宽阔冷锋雨带的形成，也将被调查。这些研究将通过对已完成的三个实地项目中收集的特殊数据集进行详细分析，并通过使用先进的中尺度模式对这些案例进行数值模拟研究来进行。***

9632580 Hobbs Cyclones in middle latitudes affect large regions of the world. Consequently, improvements in understanding and forecasting of weather associated with middle-latitude cyclones has been one of the major goals of 20th century meteorology. Although very significant advances have been made in the basic understanding and ability to forecast extratropical cyclones on the large (synoptic) scale, progress in forecasting local precipitation and severe weather associated with these systems has been much slower. This is attributed to insufficient understanding of processes and phenomena on the convective scale (~0.1-10 km) and mesoscale (~10-1000 km). For the past twenty years or so, the cloud physics research group at the University of Washington has studied extratropical cyclones, with emphasis on the microphysics and mesoscale aspects of precipitation. These studies led to a classification and study of rainbands on the west coast of the United States, and studies of cyclones on the US east coast and in the central US. The latter two studies led to a proposal for a new conceptual model for cyclones that are generated in the lee of the Rocky Mountains, as well as to the identification of two large-scale rainbands that can produce severe weather in the central United States. The present research is an extension of these studies. Three main areas of research will be pursued. The first is to carry out further evaluations of the new conceptual model for cyclones in the central United States in order to improve its observational and theoretical foundation, and to increase its utility as a weather forecasting aid. The second task is to investigate the mechanisms responsible for the formation of narrow cold frontal rainbands, which are a ubiquitous feature of extratropical cyclones and can produce severe local weather. The formation of wide cold-frontal rainbands, another common feature of cyclones, will also be investigated. These studies will be carried out through detailed analyses of special data sets collected in three already completed field projects, and through numerical modeling studies of these cases using an advanced mesoscale model. ***