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

平原夜间高空对流(山核桃)现场活动将于2015年夏季在大平原中部进行。山核桃的科学重点是夜间对流，有四个单独的研究主题需要解决：1)夜间对流的启动和中尺度对流团的早期演变；2)钻孔和其他波状扰动；3)夜间中尺度对流系统的动力学和微物理；4)夜间对流的启动和演变的预测。观测行动计划要求三架研究飞机，七个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括固定和移动的山核桃综合探测阵列(PISA)单元，该单元由各种剖面仪器组成。山核桃更广泛的社会影响是为了水文、能源、农业和公共安全目的改善对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加强多样性。还将进行公众宣传。通过这个奖项，皮加卢斯将担任山核桃的首席预报员。为了促进这一作用，我们将使用数据同化来运行天气研究和预报(WRF)模式的实时配置。智力优势：升高的中尺度对流系统(MCS)，特别是那些发生在夜间的系统，对预报员来说是一个困难的挑战。这些事件更难准确模拟，部分原因是地面上的观测不足，但也是因为对其启动和维护的了解不足。MCS的启动和形态演变很可能受到一些特征的影响，例如在模式中没有很好地初始化的孔、凸起的边界和其他凸起的辐合区，因此这些特征如何调节对流还没有被很好地理解。这些特征经常与低空急流(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有助于更好地了解MCS。更广泛的影响：这项工作将提高对夜间MCSs的理解，这将导致对这些具有挑战性的事件的更好预测，并加强对帮助进行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对这种天气灾害的安全性。

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.