Understanding the Predictability of Initiation and Morphological Evolution of PECAN (Plains Elevated Convection at Night) Nocturnal Mesoscale Convective Systems

了解 PECAN（夜间平原高对流）夜间中尺度对流系统的起始和形态演化的可预测性

• 批准号: 1359606
• 负责人: William Gallus
• 金额: $ 9.15万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1359606&HistoricalAwards=false
• 关键词: Understanding; Predictability; Initiation; Morphological; Evolution

The Plains Elevated Convection at Night (PECAN) field campaign will occur the Summer of 2015 in the central Great Plains. The scientific focus of PECAN is nocturnal convection, with four separate research topics to be addressed: 1) Nocturnal convection initiation and early evolution of mesoscale convective clusters; 2) Bore and other wave-like disturbances; 3) Dynamics and microphysics of nocturnal mesoscale convective systems; 4) Prediction of nocturnal convection initiation and evolution. The observational campaign plan calls for three research aircraft, seven mobile Doppler radars, and multiple sounding systems. A main part of the experimental design is the inclusion of fixed and mobile PECAN Integrated Sounding Array (PISA) units which consists of a variety of profiling instruments. The broader societal impact of PECAN is to improve forecasts of these nocturnal events for hydrology, energy, agriculture and public safety purposes. The field campaign would include a large number of students, including efforts to broaden participation and enhance diversity. Public outreach would also be conducted. Via this award, PI Gallus will serve as lead forecaster for PECAN. To facilitate this role, we will run a real-time configuration of the Weather Research and Forecasting (WRF) model using data assimilation.Intellectual Merit :Elevated mesoscale convective systems (MCSs), particularly those occurring at night, are a difficult challenge for forecasters. These events are more difficult to accurately simulate, partly because of insufficient observations above ground level, but also due to deficiencies in understanding of their initiation and maintenance. Initiation of and morphological evolution within MCSs is likely influenced by features such as bores, elevated boundaries, and other elevated convergence zones that are not initialized well in the models, and thus how these features modulate convection is not well-understood. These features often coexist with low-level jets (LLJ) whose simulation is also sensitive to errors in the simulated planetary boundary layer evolution. Tools and knowledge gained by this award will provide a better understanding of MCSs. Broader Impacts :This work will lead to both improved understanding of elevated nocturnal MCSs that should lead to improved forecasting of these challenging events, and enhanced education and training of students who will assist in conducting the research and also the forecasting in the field. This work has the potential to directly improve safety from this weather hazard.

平原夜间高对流 (PECAN) 实地活动将于 2015 年夏季在大平原中部进行。 PECAN的科学重点是夜间对流，有四个独立的研究课题需要解决：1）夜间对流起始和中尺度对流星团的早期演化； 2) 钻孔和其他波状扰动； 3）夜间中尺度对流系统动力学与微观物理； 4）夜间对流产生和演化的预测。 观测活动计划需要三架研究飞机、七架移动多普勒雷达和多个探测系统。 实验设计的一个主要部分是包含固定和移动 PECAN 集成探测阵列 (PISA) 装置，该装置由各种分析仪器组成。 PECAN 更广泛的社会影响是改善对水文、能源、农业和公共安全目的的这些夜间事件的预测。 实地活动将包括大量学生，包括努力扩大参与和增强多样性。 还将开展公共宣传活动。 通过该奖项，PI Gallus 将担任 PECAN 的首席预测员。为了发挥这一作用，我们将使用数据同化来运行天气研究和预报 (WRF) 模型的实时配置。 智力优势：高中尺度对流系统 (MCS)，特别是在夜间发生的对流系统，对预报员来说是一个艰巨的挑战。这些事件更难以准确模拟，部分原因是地面以上观测不足，但也由于对其引发和维护的了解不足。 MCS 内的启动和形态演化可能受到模型中未很好初始化的孔、高架边界和其他高架汇聚区等特征的影响，因此这些特征如何调节对流尚不清楚。这些特征通常与低空急流 (LLJ) 共存，低空急流的模拟对模拟行星边界层演化中的误差也很敏感。 通过该奖项获得的工具和知识将有助于更好地理解 MCS。更广泛的影响：这项工作将提高对夜间 MCS 升高的理解，从而改进对这些具有挑战性的事件的预测，并加强对协助开展研究和现场预测的学生的教育和培训。 这项工作有可能直接提高这种天气灾害的安全性。