Synoptic and Mesoscale Structure and Evolution of Occluded Winter Storms and Their Associated Precipitation Bands

虽然对锋面和气旋的大尺度方面的研究已经进行了若干年，但对区域和地方尺度特征的了解并不多。 这项研究的目的是扩展以前的结构，动力学和降水分布与闭塞的冬季气旋的研究。 研究的一个组成部分是利用最近的SNOWBAND现场试验中收集的前所未有的观测数据集记录暖闭塞的细尺度结构和降水分布。 在这一部分的研究中，将讨论有关暖闭塞的中尺度结构以及负责气旋闭塞区大雪带的产生和维持的中尺度动力过程的问题。研究闭塞区沿着运行的非地转动力学，并检查闭塞象限的静力稳定性的演变也是研究的组成部分。 此外，分段位涡诊断将专门研究离散位涡异常在改变成熟气旋锋面结构中的作用。 这项研究的成功完成，应产生重要的进展，有助于理解的过程，结构，动力学和降水分布特征的热带气旋。

While the larger-scale aspects of fronts and cyclones has been studied for some years, the regional and local-scale characteristics are not as well known. This research aims to extend prior studies of the structure, dynamics, and precipitation distribution associated with occluded winter cyclones. This work will be accomplished through employment of a case study approach involving analysis of observations and diagnosis of output from high resolution numerical simulations of selected events performed using an advanced mesoscale numerical model.A component of the research will focus on documenting the fine-scale structure and precipitation distribution of warm occlusions using the unprecedented observational data set collected during the recent SNOWBAND field experiment. Questions regarding the mesoscale structure of warm occlusions as well as the mesoscale dynamical processes responsible for the production and sustenance of heavy snowbands in the occluded sector of cyclones will be addressed in this component of the research.Investigation of the ageostrophic dynamics operating in the occluded sector along with an examination of the evolution of the static stability in the occluded quadrant are also components of the research. In addition, piece-wise potential vorticity (PV) diagnostics will be employed to specifically examine the role of discrete PV anomalies in altering the frontal structure of mature cyclones. Successful completion of this research should produce important advances in understanding of the processes that contribute to the structure, dynamics and precipitation distribution characteristic of extratropical cyclones.