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.

平原夜间高架对流（PECAN）现场活动将于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要解决：1）夜间对流启动和中尺度对流团的早期演变; 2）孔和其他波状扰动; 3）夜间中尺度对流系统的动力学和微物理; 4）夜间对流启动和演变的预测。 观测活动计划需要三架研究飞机、七部移动的多普勒雷达和多种探测系统。 实验设计的一个主要部分是包括固定和移动的PECAN集成探测阵列（比萨）单元，该单元由各种剖面仪器组成。 PECAN的更广泛的社会影响是为了水文、能源、农业和公共安全的目的改善对这些夜间事件的预报。 实地活动将包括大量学生，包括努力扩大参与和加强多样性。 还将开展公共外联活动。 通过这个奖项，PI Gallus将担任PECAN的首席预报员。为了促进这一作用，我们将运行一个实时配置的天气研究和预报（WRF）模式使用dataassimilation.Intellectual优点：升高的中尺度对流系统（MCS），特别是那些发生在晚上，是一个困难的挑战预报员。这些事件更难以准确模拟，部分原因是地面上的观测不足，但也是由于对其启动和维持的理解不足。MCSs内的启动和形态演变可能受到诸如孔、升高的边界和其他在模型中未初始化良好的升高的会聚区等特征的影响，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，后者的模拟对模拟的行星边界层演变中的误差也很敏感。 通过该奖项获得的工具和知识将提供对MCS的更好理解。更广泛的影响：这项工作将有助于提高对夜间MCSs升高的理解，从而改善对这些具有挑战性的事件的预测，并加强对学生的教育和培训，帮助他们进行研究和预测。 这项工作有可能直接提高这种天气危害的安全性。