A Reappraisal of Petterssen's Type A and Type B Cyclogenesis - A Dynamical Process Study

气旋生成是一个概括性术语，指的是由与行星同向旋转的向内螺旋风驱动的大气封闭、低压、圆周运动的发展或加强。温带气旋形成于沿着锋面（斜压带），并发展成冷心气旋。这与热带气旋不同，后者是由与强烈对流相关的潜热驱动的，是温暖的中央核心系统。热带气旋在沿着锋面边界经过时，会按照一个可预测的顺序演变，这一概念导致了各种分类和诊断方案的发展。Petterssen和Smebye（1950年）提出的一个这样的方案采用了两种广泛的发展路径，A型（由低水平过程指导）和B型（由高水平过程指导）。这些不同的强迫项负责向上的垂直运动和发展的动能系统。 尽管这种分类方法被广泛使用，但温带气旋动力过程的细节仍然不清楚。该项目分析了FASTEX（锋面和大西洋风暴实验，1997年）和沿着其他选定的数据集期间观察到的一些气旋事件，试图采用两种不同的方法来更好地诊断和解释这两种类别类型。 这些方法分别是基于Q矢量分析的常规准营养分析，以及伴随模型导出的敏感性分析，两者都识别与中纬度气旋发展相关的大气参数（例如，切变和横向垂直运动）。这些研究的更广泛的影响包括促进威斯康星州大学学生的本科和研究生教育，社区资源的开发和调查的新方法，在天气预报研究的主题外热带气旋的发展。2009-2010年美国冬季风暴等热带气旋对经济的影响就是这方面的重要例子。

Cyclogenesis is overarching term for the development or strengthening of a closed, low pressure, circular motion of the atmosphere driven by inward spiraling winds rotating in the same direction as the planet. Extratropical cyclones form along weather fronts (baroclinic zones) and mature into cold core cyclones. This is distinct from tropical cylcones which are driven by the latent heat associated with intense convection and are warm, central core systems. The notion that extratropical cyclones evolve through a predictable sequence as they pass along the frontal boundary has led to the development of a variety of classification and diagnostic schemes. One such scheme, due to Petterssen and Smebye (1950's), adopts two broad developmental paths, Type A (directed by low level processes) and Type B (directed by upper level processes). These differ as to the forcing terms responsible for upward vertical motion and development of the kinetic energy in the systems. Despite the widespread use of this classification, details of the dynamical processes in extratropical cyclones remains unclear. This project, analyzing a number of cyclogenesis events observed during FASTEX (the Fronts and Atlantic Storms Experiment, 1997) and along with other selected data sets, seeks to employ two different methodologies to better diagnose and interpret the two category types. These methodologies are respectively conventional quasigesotrophic analyses based on Q vector analysis, and an adjoint model derived sensitivity analysis, both identifying atmospheric parameters (e.g. shearwise and transverse vertical motions) that relate to mid latitude cyclone development. Broader impacts of these studies include the furtherance of undergraduate and graduate education of University of Wisconsin students, development of community resources and the investigation of new methodologies in weather predictability research on the topic of extratropical cyclone development. The economic impact of extratropical cyclones such as the 2009-2010 US winter storms were significant examples thereof.