A Multiscale Diagnostic and Prognostic Investigation of Environmental Influences on Tropical Cyclone Life Cycles

本研究的目的是对热带气旋从发生到温带过渡（ET）进行详细的诊断和预测分析。研究将分两个阶段进行。在第一阶段，将对历史上的风暴以及所有大西洋热带气旋在一到两个完整的风暴季节进行详细的诊断分析。每一个风暴的生命历程将被跟踪和记录，从热带低气压定义前几天开始，到风暴消散或经历温带转变时结束。第一阶段的目标是确定造成大西洋盆地热带气旋发展的各种热带和中纬度扰动。此外，还将研究重大旋流/转变事件对大尺度流动的高级影响。在第二阶段，将对有代表性的风暴进行数值模拟，以检验从第一阶段完成的诊断分析中制定的物理假设。热带气旋的形成、强度变化、环流和热带转变发生在各种大尺度热带和亚热带环境中。每一个事件可能是由于大尺度气流中单个特征的存在（例如，东风波、中纬度高空槽或位涡[PV]异常），也可能涉及气流中多个特征的相互作用。单特征和多特征环境强迫在热带气旋形成和温带转变中的作用尚不清楚，需要量化。诊断一个风暴季节内的所有风暴将解决一次性强迫和多次强迫事件的相对重要性。本研究中使用的主要数据集将是操作网格分析字段。将利用由卫星产生的丰富的对流层上层水风。现有的数据集将允许对海洋上空的热带气旋形成和温带过渡进行详细分析。这一提议的更广泛影响源于这样一个事实，即热带气旋在其生命周期的任何阶段都可能对海上水手、沿海居民和内陆居民的生命和财产构成严重威胁。通过对热带气旋生命周期谱的详细研究，希望所获得的基本知识可在热带气旋路径/强度预报和定量降水估计方面有实际应用。该项目还提供了与各种政府和民间机构以及其他教育机构合作的机会，以帮助促进向业务部门和学生传授知识。

The purpose of this research is to conduct detailed diagnostic and prognostic analyses of tropical cyclones from genesis to extratropical transition (ET). The research will be conducted in two stages. In stage one, a detailed diagnostic analysis will be conducted for historical storms as well as all Atlantic tropical cyclones over the course of one or two complete storm seasons. The life history of each storm will be tracked and documented beginning several days before tropical depression definition and ending when the storm has dissipated or undergone extratropical transition. The goal of stage one is to identify the variety of tropical and midlatitude disturbances responsible for the development of tropical cyclones in the Atlantic basin. Further, the upscale impact of significant cyclogenesis/transition events on the large-scale flow will also be examined. In stage two, numerical simulations of representative storms will be conducted to test physical hypotheses formulated from the diagnostic analyses completed in stage one. Tropical cyclogenesis, intensity changes, recurvature, and tropical transition occur across a variety of large-scale tropical and subtropical environments. Each event may result from the presence of a single feature in the large-scale flow (e.g., easterly wave; midlatitude upper-level trough or potential vorticity [PV] anomaly) or may involve the interaction of multiple features in the flow. The contribution of single-feature and multiple-feature environmental forcings in tropical cyclogenesis and extratropical transition remains unclear and needs to be quantified. Diagnosing all storms within a storm season will address the relative importance of one-time forcing and multiple forcings events.The primary datasets used in this study will be operational gridded analyses fields. Advantage will be taken of the abundant satellite-derived upper-tropospheric water winds. The available datasets will allow for the detailed analysis of tropical cyclogenesis and extratropical transition over the oceans.The broader impacts of this proposal follow from the fact that tropical cyclones at any stage of their life cycle can pose a serious threat to life and property to mariners at sea, to coastal residents and to inland inhabitants. By examining a spectrum of tropical cyclone life cycles in detail it is hoped that the basic knowledge gained may have operational application in the area of tropical cyclone track/intensity forecasting and quantitative precipitation estimation. This project also presents the opportunity to work with various government and civilian agencies and other educational institutions to help facilitate the transfer of knowledge to operations and to students.