Collaborative Research: The Relationships between Sheared Convective Clouds and Tropical Cyclone Evolution

合作研究：切变对流云与热带气旋演化的关系

• 批准号: 1140357
• 负责人: Wesley Terwey
• 金额: $ 16.67万
• 依托单位: University of South Alabama
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1140357&HistoricalAwards=false
• 关键词: Collaborative; Research; Relationships; between; Sheared

Despite improving observational and computational resources, the forecasting of tropical cyclone (TC) structural and intensity evolution is still a significant challenge. The limits of predictability relate to the nonlinear interactions between a TC's multi-scale dynamics and its environment. Recent research underscores how TC evolution is influenced strongly by the details of latent heating. As such, properly accounting for convective processes in TCs is a key step towards a more complete physical understanding of TCs and improved prediction. Yet, potentially essential aspects of convective-scale dynamics remain unresolved. The detailed structure of kinematic and thermodynamic properties found within TCs can provide a broad spectrum of distinct local environments resulting in a variety of convective and mesoscale cloud morphologies. Each convective mode may have unique impacts on TC evolution.Intellectual merit:To advance the understanding of convective-scale processes in TCs, this multi-framework study will investigate the interactions of vertical and horizontal wind shear with both isolated convective clouds and more organized rainbands. Through this research effort, the following questions will be examined:1. How do strong horizontal wind shear and background absolute vertical vorticity impact isolated convective clouds and rainbands?2. What are the primary interactions that occur between horizontal and vertical shears and convection?3. How does the response of convection to three-dimensional shear vary given the variations of ambient thermodynamic conditions within TCs?4. What are the implications of the various convective modes resulting from kinematic and thermodynamic variability on overall TC dynamics?The multiple frameworks for this study will include an idealized cloud model, high-resolution flight-level Doppler radar and in situ observations of TCs, and two full-physics TC simulations. Sensitivity experiments with a cloud model will be used to understand how three-dimensional wind shear and thermodynamic variability within TCs govern isolated convective clouds and convective systems. The impacts of sheared convection on the mean flow will also be documented in the cloud model. The observational analyses and TC simulations will provide realistic settings to evaluate the idealized cloud modeling results and to deduce feedbacks and relationships between the various sheared convective modes, rainbands, and TC dynamics. Vorticity, potential vorticity, and thermodynamic budgets and general statistical analysis of cloud, precipitation, and cold pool properties will be the primary tools of analysis for elucidating open questions related to sheared TC convection.Broader impacts:The research will shed new light into basic internal dynamical processes related to TC intensity and structure change and it will have more general theoretical impacts outside of TC research. The resulting peer-reviewed publications will provide both applied and theoretical contexts in which both researchers and forecasters can interpret convective scale processes in TCs. Improvement in forecasting TCs and convective-scale processes in TCs will in turn be beneficial to society. The research team will work with the Center for Hurricane Intensification and Landfall Investigation and talented and motivated undergraduate/graduate students who will contribute to significant aspects of the research and subsequent, peer-reviewed publications. A webpage containing animations of key experimental results will supplement research articles and will also aid in college classroom instruction and other outreach efforts such as scientific high school workshops.

尽管观测和计算资源不断改善，但热带气旋（TC）结构和强度演变的预报仍然是一个重大挑战。 可预报性的限制与热带气旋的多尺度动力学与其环境之间的非线性相互作用有关。最近的研究强调了TC演变如何受到潜热加热细节的强烈影响。 因此，正确解释热带气旋中的对流过程是实现对热带气旋更完整的物理理解和改进预测的关键一步。 然而，对流尺度动力学的潜在重要方面仍然没有得到解决。 TC内的运动学和热力学特性的详细结构可以提供广泛的不同的局部环境，从而产生各种对流和中尺度云形态。 每一种对流模式都可能对热带气旋的演变产生独特的影响。学术价值：为了加深对热带气旋中对流尺度过程的理解，这项多框架研究将研究垂直和水平风切变与孤立对流云和更有组织的雨带的相互作用。 通过本研究，将探讨以下问题：1。强烈的水平风切变和背景绝对垂直涡度如何影响孤立的对流云和雨带？2.在水平切变和垂直切变与对流之间发生的主要相互作用是什么？3.对流对三维剪切的响应如何随TC内环境热力学条件的变化而变化？4.由运动学和热力学变化引起的各种对流模式对整体TC动力学有什么影响？这项研究的多个框架将包括一个理想化的云模型，高分辨率飞行水平多普勒雷达和TC的原位观测，以及两个全物理TC模拟。云模式的敏感性实验将用于了解TC内的三维风切变和热力学变化如何控制孤立的对流云和对流系统。 切变对流对平均气流的影响也将记录在云模式中。 观测分析和TC模拟将提供现实的设置，以评估理想化的云模拟结果，并推断反馈和各种剪切对流模式，雨带和TC动力学之间的关系。涡度，位涡，热力学预算和一般的云，降水和冷池属性的统计分析将是主要的分析工具，用于阐明有关剪切TC convention.Broader影响的开放性问题：这项研究将揭示新的光到基本的内部动力过程有关TC强度和结构的变化，它将有更一般的理论影响TC研究之外。 由此产生的同行评议的出版物将提供应用和理论背景，研究人员和预报员可以解释TC中的对流尺度过程。 改进热带气旋预报和热带气旋中对流尺度过程的预报将对社会有益。 研究团队将与飓风强化和登陆调查中心以及有才华和有动力的本科生/研究生合作，他们将为研究的重要方面和随后的同行评审出版物做出贡献。 一个包含关键实验结果动画的网页将补充研究文章，也将有助于大学课堂教学和其他推广工作，如科学高中研讨会。