Basic Mechanisms of Tropical Cyclone Size and Structure Change

以前对热带气旋与其大尺度环境的相互作用的研究主要集中在风暴路径的环境控制上，最近则集中在强度的快速变化上。通过对存档的风暴观测资料的回顾和分析，以及采用NCAR/PSU MM5中尺度模式嵌套至3公里水平分辨率的理想化模拟，本研究将调查以前未被探索的问题，即是什么环境因素控制了热带气旋的大小（即直径）和这些风暴的其他广泛结构方面。由于现有的业务天气预报模式通常能很好地反映热带气旋所处的大尺度环境，因此，识别那些对确定气旋大小和结构最重要的环境特征，将改善预报风暴结构及其演变。这项研究的智力价值在于提高了对控制飓风规模演变的基本物理过程的理解，以及伴随破坏性风和强降水的广泛结构配置。这项工作的更广泛影响包括培训大学研究生和本科生以及支持代表性不足的群体的参与。预测热带气旋大小变化的技术的改进，将反过来影响业务产品，包括风暴潮预测，以及在飓风登陆时制定海岸疏散计划的适当范围（在空间和时间上）。

Previous studies of the interaction of tropical cyclones with their large-scale environments have focused primarily on environmental controls on storm tracks and, more recently, rapid changes in intensity. Through a combination of review and analysis of archived storm observations and idealized simulations employing the NCAR/PSU MM5 mesoscale model nested down to 3-km horizontal resolution, this research will investigate the previously unexplored issue of what environmental factors control tropical cyclone size (i.e., diameter) and other broad structural aspects of these storms. Since the large-scale environments in which tropical cyclones are embedded are generally well represented by existing operational weather forecast models, it follows that identifying those environmental characteristics that are most important to determining cyclone size and structure will improve forecasts storm structure and its evolution.The intellectual merit of this research centers upon achieving improved understanding of fundamental physical processes that control evolution of hurricane size and broad structural configuration of accompanying envelopes of damaging winds and heavy precipitation.Broader impacts of this work include training of university graduate and undergraduate students and support of the participation of underrepresented groups. Improved techniques for forecasting changes of tropical cyclone size will in-turn impact operational products including storm surge prediction and proper scoping (in space and time) of coastal evacuation plans in the face of landfalling hurricanes.