Studies of the Internal Structure and Dynamics of Convective Weather Systems

对流天气系统的内部结构和动力学研究

• 批准号: 0133506
• 负责人: Paul Markowski
• 金额: $ 48.04万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-15 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0133506&HistoricalAwards=false
• 关键词: Studies; Internal; Structure; Dynamics; Convective

The Principal Investigator will investigate the internal structure and dynamics of the convective region of mesoscale convective systems. The main goal is to determine why moist convection appears as discrete thunderstorms in some situations and as solid mesoscale swaths (slabs) of overturning in others. Specific objectives include 1) constructing characteristic inflow environments for discrete-thunderstorm events and for slab events, 2) determining the local (within the convective region) differences in the dynamic and thermodynamic conditions that accompany cellular vs. slab convection, and 3) determining how differences in the convection (slab vs. cellular) affect the mesoscale dynamics and structural properties of the convective system.The research methodology is composed of three parts: 1) construction of a composite environment for observed cases of predominantly cellular convective systems and for systems exhibiting solid-slab overturning, 2) numerical experiments on the composite environments to determine whether or not the model is able to generate the two types of organizational modes, and 3) numerical sensitivity experiments on idealized (analytically specified) initial conditions using the results of items (1) and (2) as a guide.It is expected that the knowledge gained from these investigations will a) help to identify the factors that establish the organizational mode of the convection and the depth and strength of moist absolutely unstable layers, and b) elucidate how those factors affect the overall structure and evolution of mesoscale convective systems. The results may also provide practical benefits, such as improvements in the ability to discriminate among the types of severe weather that will occur for various types of large-scale environments. Differentiating among the possible modes of convective organization is extremely important from a forecasting perspective since it is these differences that often determine whether or not severe weather will occur and, if so, whether it will be characterized by individual, possibly rotating, storms or by strong straight line winds associated with slab convection.

首席研究员将研究中尺度对流系统对流区的内部结构和动力学。 主要目标是确定为什么湿对流在某些情况下表现为离散的雷暴，而在其他情况下表现为固体中尺度带（板块）的翻转。 具体目标包括：1）构建离散雷暴事件和平板事件的特征入流环境，2）确定当地的（在对流区域内）伴随胞状对流与平板对流的动力学和热力学条件的差异，以及3）确定对流的差异如何（平板与蜂窝）对对流系统中尺度动力学和结构特性的影响。研究方法由三部分组成：1）为观察到的主要细胞对流系统的情况和表现出固体板翻转的系统构建复合环境，2）对复合环境进行数值实验以确定模型是否能够产生两种类型的组织模式，3）理想化的数值敏感性实验（分析规定的）初始条件，以第（1）和（2）项的结果为指导。预计从这些研究中获得的知识将a）有助于确定建立对流组织模式的因素以及潮湿绝对不稳定层的深度和强度，和B）阐明这些因素如何影响中尺度对流系统的整体结构和演变。 这些结果还可能提供实际好处，例如提高区分各种类型的大规模环境中将发生的恶劣天气类型的能力。 从预报的角度来看，区分可能的对流组织模式是非常重要的，因为正是这些差异往往决定了是否会发生恶劣天气，如果是这样，它是否会以单独的，可能旋转的风暴或与板状对流相关的强烈直线风为特征。