CAREER: Multiscale Investigation of Warm-Season Precipitation Extremes

职业：暖季极端降水的多尺度调查

• 批准号: 0954908
• 负责人: Russ Schumacher
• 金额: $ 60.48万
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2011-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0954908&HistoricalAwards=false
• 关键词: CAREER; Multiscale; Investigation; Warm; Season

This study will examine the processes and predictability associated with midlatitude warm-season extreme precipitation on multiple spatial and temporal scales. Despite the great need for accurate precipitation forecasts and flood warnings, the prediction of warm-season heavy rainfall continues to be one of the greatest challenges in weather forecasting. Investigating the weather systems that produce extreme rainfall and deadly flash flooding will provide us with basic understanding of these systems.The ultimate goal of this research is to improve prediction of the weather systems that lead to extreme warm-season precipitation. This research will identify the mechanisms that enhance or limit predictability in warm-season convective systems. Intellectual merit. One focus of this research will be elevated, linear mesoscale convective systems (MCSs) that have been observed to produce extreme local rainfall and flash flooding. The lack of knowledge about elevated, organized convection limits the ability to produce accurate forecasts and warnings of potential flash-flood situations. To address this issue, numerical simulations will be conducted to quantify the large-scale controls on the initiation, organization, and rainfall production of elevated linear MCSs, particularly the respective roles of tropical, subtropical, and midlatitude influences. These simulations will also be combined with observations to quantify the interactions between frontogenetical circulations and convective-scale processes in the evolution of these MCSs.At larger scales, widespread, multiple-day heavy rainfall events, such as those that affected the Southern Plains of the United States in 2007 and the Midwest in 2008, have far-reaching impacts. In some cases, the heavy rainfall occurs in association with a series of feedbacks between deep convective activity and the development and maintenance of long-lived, slow-moving circulations at the mid-levels of the atmosphere. Preliminary research has shown that events such as this have low predictability at the medium range. This research will create an observational climatology of heavy rainfall associated with such mesoscale circulations. Then, ensemble forecast data will be used to assess the predictability of these events, the processes that lead to their development and to the success or failure of numerical forecasts, and their larger-scale effects.Broader impacts. Extreme precipitation, and uncertainties in predicting it, can also have considerable impacts on society. This study integrates research and education by introducing students in the atmospheric sciences to research methods that explore these impacts. Graduate students will be trained in established social-science methods, and a multidisciplinary undergraduate course will be developed to provide the basis for discussions and inquiry into the relationship between weather and society. The meteorological research on extreme rainfall described above will be enhanced by performing student-designed societal analyses of local flood and flash-flood events. A regional workshop will bring together students, researchers, practitioners, and stakeholders to forge new collaborations and to address the complex challenges associated with extreme rainfall. Furthermore, integrated analyses of weather events will engage the public, and will reveal areas where forecasts and warnings can be improved from both the meteorological and societal perspective.

这项研究将检查与多个空间和时间尺度上的中纬度暖季极端降水相关的过程和可预测性。 尽管非常需要准确的降水预测和洪水警告，但预测温季大雨仍是天气预报中最大的挑战之一。 调查产生极端降雨和致命山洪的天气系统将为我们提供对这些系统的基本理解。这项研究的最终目标是改善对导致极端温暖降水的天气系统的预测。 这项研究将确定增强或限制温暖对流系统可预测性的机制。 智力优点。 这项研究的一个重点将提升，线性中尺度对流系统（MCS）被观察到会产生极端的局部降雨和山洪泛滥。 缺乏有关提高，有组织的对流的知识限制了产生准确的预测和警告潜在闪光灯情况的能力。 为了解决这个问题，将进行数值模拟，以量化线性MCS的启动，组织和降雨产生的大规模控制，尤其是热带，亚热带和中纬度影响的各自作用。 这些模拟还将与观察结果结合在一起，以量化这些MC的演变中构源循环和对流尺度过程之间的相互作用。在较大的规模，广泛的，多天的大降雨事件中，例如影响2007年美国南部平原和2008年中西部地区的南部平原的事件，其影响很大。 在某些情况下，大降雨发生在深度对流活动与在大气中间层次中长寿，缓慢移动的循环的发展和维护之间的一系列反馈。 初步研究表明，诸如此类的事件在中等范围内的可预测性较低。这项研究将创建与此类中尺度循环相关的大雨的观察气候。 然后，集合预测数据将用于评估这些事件的可预测性，导致其发展的过程以及数值预测的成功或失败及其较大规模的效果。 极端的降水和预测的不确定性也会对社会产生相当大的影响。 这项研究通过将大气科学中的学生介绍给探索这些影响的研究方法来整合研究和教育。 研究生将接受既定的社会科学方法的培训，并将开发多学科的本科课程，为讨论和调查天气与社会之间的关系提供基础。 对上述极端降雨的气象研究将通过对当地洪水和闪光洪水事件进行学生设计的社会分析来增强。 区域研讨会将召集学生，研究人员，从业人员和利益相关者进行新的合作，并应对与极端降雨相关的复杂挑战。 此外，对天气事件的综合分析将吸引公众，并将揭示从气象和社会观点可以改善预测和警告的领域。