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

环境对热带气旋生命周期影响的多尺度诊断和预测研究

• 批准号: 0553017
• 负责人: Lance Bosart
• 金额: $ 53.98万
• 依托单位: SUNY at Albany
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0553017&HistoricalAwards=false
• 关键词: Multiscale; Diagnostic; Prognostic; Investigation; Environmental

The focus of the research will be on multiscale diagnostic investigations of tropical cyclone (TC) life cycles and TC-environmental interactions. It builds and expands upon completed and ongoing research on TCs, particularly in the areas of tropical transition (TT) and extratropical transition (ET). The TT process is less well understood and has been a significant focus of ongoing work, and will be a major focus of this grant research. A cornerstone of the TT process is that incipient storm formation occurs in environments characterized by horizontal temperature gradients and associated vertical wind shear that are more characteristic of mid latitudes than the tropics. A precursor upper-level disturbance of mid latitude origin is needed to initiate the TT process. Ascent associated with the precursor disturbance helps to moisten mid levels of the atmosphere, preventing widespread evaporative cooling associated with convective downdrafts, and facilitating column warming. Multiple convective elements in the storm's circulation then consolidate, completing the transition to a warm-core TC. This view of the TT process has arisen from project-related analysis and modeling studies of Hurricanes Diana (1984), Michael (2000), Humberto (2001), Catarina (2004) and Alex (2004). Catarina (2004), a serendipitous event, was noteworthy for being the first-ever recorded South Atlantic hurricane. Storm environmental interactions will be assessed through the impact of upper-level disturbances on TC life cycles, and through TC-induced changes in the environmental flow. Examples of the former include TC development via the TT process. Examples of the latter include TC-related convectively modified shear and potential vorticity profiles in the immediate and downshear TC environment. The PI and his graduate students will also focus on documenting the origin of mesoscale substructure within landfalling TCs, including ET storms. Examples include Floyd (1999), noteworthy for coastal front-related flood-producing rains, and weaker storms such as Chris (1988), Marco (1990) and Jerry (1995), noteworthy for exceptionally heavy precipitation concentrated near weak frontal boundaries. The diagnostic TC cases studies will be used to establish the synoptic-dynamic context for understanding the various aspects of TC life cycles. The envisioned multiscale diagnostic studies will focus on identifying antecedent disturbances that contribute to TC evolution and document the large-scale flow regimes and regime transitions that occur in conjunction with TC-environmental interactions. This task is motivated by completed and ongoing research that has shown that the precipitation distribution associated with ET storms can be understood in terms of fundamental dynamical principles. In terms of broader impacts, existing weather prediction models do a relatively poor job of predicting the development of TCs that originate by the TT process. Given that TT developments can occur near the populous southeast US coast, it is important to learn more about how such storms develop and intensify. TT storms also pose a serious threat (wind and waves) to marine interests in the heavily traveled coastal shipping lanes. Landfalling and transitioning (ET) storms can also pose significant forecasting challenges. They can adversely impact marine interests (wind and waves), coastal residents/businesses (high winds, tornadoes, and flooding from storm surges), and inland residents/businesses (fresh-water flooding due to heavy rain). This project also presents the opportunity to work with various government agencies (e.g., National Hurricane Center) and other educational institutions (an ongoing activity) to help facilitate the transfer of research knowledge to operations and students. Research findings will be disseminated through: 1) conference and workshop presentations, 2) refereed papers, and 3) presentations at COMET mini-courses, workshops for operational forecasters, and conferences for educators.

研究的重点将是热带气旋生命周期的多尺度诊断调查以及热带气旋与环境的相互作用。它在已完成和正在进行的关于热带气候变化的研究的基础上发展和扩展，特别是在热带过渡(TT)和温带过渡(ET)领域。技术转让过程不太为人所知，一直是正在进行的工作的一个重要重点，也将是这项赠款研究的主要重点。TT过程的一个基石是，风暴的初期形成发生在具有水平温度梯度和相关的垂直风切变的环境中，这些环境更多地是中纬度而不是热带的特征。启动TT过程需要一个起源于中纬度的前兆高层扰动。与前兆扰动相关的上升有助于润湿大气的中层，防止与对流下沉气流相关的大范围蒸发冷却，并促进柱子变暖。风暴环流中的多个对流要素随后巩固，完成了向暖核热带气旋的过渡。对飓风“戴安娜”(1984年)、“迈克尔”(2000年)、“温贝托”(2001年)、“卡塔琳娜”(2004年)和“亚历克斯”(2004年)进行的与项目有关的分析和模拟研究，就产生了对技术转让过程的这种看法。卡特琳娜(2004)是一个偶然事件，值得注意的是，它是有记录以来第一个南大西洋飓风。风暴与环境的相互作用将通过高层扰动对热带气旋生命周期的影响以及热带气旋引起的环境流量变化来评估。前者的例子包括通过技术转让过程开发技术转让。后者的例子包括与热带气旋有关的对流修改的切变和位涡廓线，在直接和下行切变的热带气旋环境中。PI和他的研究生还将专注于记录正在登陆的TC中的中尺度亚结构的起源，包括ET风暴。例子包括弗洛伊德(1999年)，值得注意的是与沿海锋面有关的洪水产生的降雨，以及较弱的风暴，如克里斯(1988年)，马可(1990年)和曾傑瑞(1995年)，值得注意的是集中在弱锋面边界附近的异常强降水。诊断性的热带气旋病例研究将被用来建立理解热带气旋生命周期的各个方面的天气-动力学背景。设想的多尺度诊断研究将侧重于确定有助于热带气旋演变的前置扰动，并记录伴随着热带气旋-环境相互作用而发生的大尺度流态和流态转变。这项任务是由已完成的和正在进行的研究推动的，这些研究表明，可以根据基本的动力学原理来理解与ET风暴有关的降水分布。就更广泛的影响而言，现有的天气预报模式在预测由TT过程引发的TCS发展方面做得相对较差。鉴于热带气旋的发展可能发生在人口稠密的美国东南海岸附近，了解更多此类风暴是如何发展和加强的，这一点很重要。热带气旋风暴(风和浪)也对频繁航行的沿海航道上的海洋利益构成严重威胁。登陆和过渡(ET)风暴也可能带来重大的预报挑战。它们可能对海洋利益(风和浪)、沿海居民/企业(大风、龙卷风和风暴潮造成的洪水)以及内陆居民/企业(暴雨造成的淡水洪水)造成不利影响。该项目还提供了与各种政府机构(如国家飓风中心)和其他教育机构合作的机会(这是一项持续的活动)，以帮助将研究知识转移给操作人员和学生。研究成果将通过以下方式传播：1)会议和研讨会报告，2)参考论文，3)在彗星小型课程、业务预报员研讨会和教育工作者会议上的报告。