EAGER: Opportunistic Soundings to Advance the Understanding of High-Shear Low-CAPE (Convective Available Potential Energy) Convective Environments

EAGER：机会性探测，以增进对高剪切低 CAPE（对流可用势能）对流环境的理解

• 批准号: 1530258
• 负责人: Matthew Parker
• 金额: $ 2.34万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1530258&HistoricalAwards=false
• 关键词: EAGER; Opportunistic; Soundings; Advance; Understanding

Severe convective storms within environments characterized by large vertical wind shear and marginal convective available potential energy (so-called "high-shear, low-CAPE", or "HSLC" environments) present a substantial threat to society, and yet they remain poorly understood. Recent studies indicate that a substantial fraction of all severe weather reports, including significant tornadoes (EF2 or greater on the enhanced Fujita scale), occur within HSLC environments. HSLC conditions occur nationwide and throughout the year, but are particularly common during the cool season and overnight, when public awareness of the severe weather threat is low. Storms within HSLC environments also tend to be poorly sampled by radar due to their comparatively small spatial dimensions compared to higher-CAPE convection, with typical echo tops of 4-6 km AGL, and mesocyclones having widths and depths of only 2-4 km. Taken altogether, HSLC storms are a significant concern due to their potential severity, their typical occurrence during non-traditional times of the day and year, and the difficulties they present to radar-based warning operations. The gap in our knowledge base is manifested in terms of the relatively low skill of severe weather watches and warnings for HSLC storms. At the most basic level, HSLC forecasts are hindered because we have very little understanding of the fundamental processes governing HSLC storms and their interactions with the ambient environment. Without targeted observations of HSLC environments, our understanding of HSLC storms is unlikely to improve.The goal of this application is to undertake a program of local sounding measurements in HSLC environments at high temporal resolution. Operations will exploit the existing North Carolina State University (NCSU) sounding system, which will enable the research team to quickly coordinate launches and to target evolving cases at very low cost. The research team will use the collected data to quantify the environmental variability in HSLC regimes and identify the strengths and weaknesses of other proxy datasets that have heretofore been used for HSLC research.Intellectual Merit:HSLC severe weather is an important societal concern that requires further research. Unfortunately, a full basic research project addressing this problem is not likely until a baseline of quality observations has been made. HSLC environments are present for many hours each year, yet their conditional probability of producing severe weather on any given day is relatively low. Thus, rather than mounting an extended field campaign (which would no doubt have an unacceptable amount of "down time"), the research team will conduct an exploratory work that is inexpensive and is able to opportunistically target the most promising days within a region where HSLC convection is common. The project period will include two distinct cold seasons, maximizing the likelihood of sampling a diversity of HSLC environments during a short grant. This work is potentially transformative because it will produce the first set of temporally dense measurements ever made in HSLC environments, thereby serving as a foundation for future basic science.Broader Impacts:All sounding launches will be performed by NCSU students. In addition to incorporating graduate students from the research team, the PI serves as co-advisor for the student-run soundings club at NCSU. These students gain hands-on experience in preparing and launching soundings, as well as analyzing the data collected. Their current funding model only allows them to launch 2-4 soundings per year. The research team will invite the soundings club to participate in all launches, which will greatly enhance the number of available launch opportunities, and will provide educational data from interesting days with severe weather potential. The PI also will incorporate the data (often in near-real time) into his course on Mesoscale Meteorology.

以大垂直风切变和边际对流可用势能为特征的环境(所谓的“高切变、低开角”或“HSLC”环境)中的强对流风暴对社会构成重大威胁，但人们对它们的了解仍然很少。最近的研究表明，很大一部分恶劣天气报告，包括重大龙卷风(增强藤田等级为EF2或更高)，都发生在HSLC环境中。HSLC在全国范围内和全年都会发生，但在凉爽的季节和夜间尤其常见，因为公众对恶劣天气威胁的意识较低。HSLC环境中的风暴也往往不能被雷达采样，因为与较高的开普敦对流相比，它们的空间维度相对较小，典型的回波顶部为4-6公里，而中气旋的宽度和深度仅为2-4公里。综上所述，HSLC风暴是一个重要的问题，因为它们的潜在严重性，它们通常发生在一天和一年中的非传统时间，以及它们给基于雷达的警报行动带来的困难。我们在知识基础上的差距表现在对HSLC风暴的恶劣天气监测和警告的技能相对较低。在最基本的层面上，HSLC预报受到阻碍，因为我们对HSLC风暴的基本过程及其与周围环境的相互作用知之甚少。如果没有对HSLC环境的有针对性的观测，我们对HSLC风暴的理解不太可能得到改善。这项应用的目标是在HSLC环境中进行高时间分辨率的局地探空测量。业务将利用现有的北卡罗来纳州立大学(NCSU)探测系统，这将使研究团队能够快速协调发射并以非常低的成本瞄准不断发展的病例。研究小组将使用收集的数据来量化HSLC制度中的环境变异性，并确定迄今为止用于HSLC研究的其他替代数据集的优势和劣势。智力优势：HSLC恶劣天气是一个需要进一步研究的重要社会问题。不幸的是，在建立质量观察的基线之前，不太可能有一个全面的基础研究项目来解决这个问题。HSLC环境每年存在许多小时，但它们在任何一天产生恶劣天气的条件概率相对较低。因此，研究小组将进行一项低成本的探索性工作，并能够在HSLC对流普遍存在的区域内抓住机会，瞄准最有希望的日子，而不是展开一场延长的现场活动(这无疑会有不可接受的“停机时间”)。项目期将包括两个不同的寒冷季节，最大限度地增加在短期赠款期间对不同的HSLC环境进行采样的可能性。这项工作具有潜在的变革性，因为它将产生有史以来在HSLC环境中进行的第一组时间密度测量，从而为未来的基础科学奠定基础。广泛的影响：所有的探空发射都将由NCSU的学生进行。除了吸收研究团队的研究生外，PI还担任NCSU学生运营的测深俱乐部的联合顾问。这些学生在准备和启动测深以及分析收集的数据方面获得了实践经验。他们目前的融资模式只允许他们每年发起2-4次探测。研究团队将邀请测深俱乐部参与所有发射，这将大大增加可用发射机会的数量，并将提供具有恶劣天气潜力的有趣日子的教育数据。PI还将把这些数据(通常是近乎实时的)纳入他的中尺度气象学课程。