Collaborative Research: Investigations of Mesoscale and Microscale Processes in Extratropical Cyclones and Mesoscale Convective Systems

控制温带气旋内降水时空变异性的动态和微物理过程仍然知之甚少。降水位置、类型和强度的变化通常由降水带状和/或嵌入对流决定，特别是在气旋的西北部和暖锋象限，锋面结构和相关的锋面环流被形变气流改变。首席调查员将开展一项全面的实地活动和数值模拟研究，解决悬而未决的科学问题，目的是增进对大陆温带气旋西北和暖锋象限降水亚结构的了解。在这项研究的过程中，将讨论以下问题：1)有组织的降水子结构的主要空间型式是什么，如条带和生成单元，它们是如何演变的？2)边界层以上和边界层内的锋面尺度系统，如暖锋、热带风暴、高空冷锋，3)这些锋面系统的热力学和运动学结构是什么，包括水汽的分布和垂直运动？4)什么不稳定和类型的中尺度强迫控制着降水亚结构的产生和演变？5)不同降水亚结构之间的微物理过程是如何变化的，后果是什么？6)在某些情况下，在饱和冰的上升过程中触发不稳定是关键的吗？是否通过释放沉积的潜热来维持不稳定？首席调查人员将利用三个移动地面观测系统获取和分析降水亚结构的详细、高分辨率观测结果，这三个系统是：阿拉巴马大学亨茨维尔移动综合廓线系统、阿拉巴马X波段移动双极化雷达、美国国家科学基金会/国家大气研究中心移动GPS高级高空探测系统、以及配备微物理探测器的国家科学基金会/国家大气研究中心C-130型飞机以及怀俄明州的云多普勒雷达和云激光雷达。他们还将使用高水平和垂直分辨率的天气研究和预报模型来模拟降水量的子结构。这些观察结果将为发展可检验的假设提供基础，这些假设可以在建模研究中系统地解决。实地活动(称为冬季风暴概况，或称犁)将有一个教育部分，有来自9所大学和大气科学系的学生参与。智力优势：动力学/微物理观测战略与高分辨率数值模拟相结合，将为以比以往更全面、更明确的方式回答关键科学问题提供基础。将在这项研究中应用的新的观测能力将从根本上提供关于这些风暴的结构、动力学和物理性质的新信息，这些风暴的规模是以前从未观察到的。更广泛的影响：在全国范围内，每年有近7000人死亡，60万人受伤，140万起事故是由恶劣的道路天气造成的，主要是在冬季，一场暴风雪造成的损失从10万美元到30亿美元不等。这项研究将提供有关冬季天气系统遥感的新见解，可直接转化为对冬季天气中尺度特征的更好的业务解释和观测战略。这项研究将有助于从根本上理解冬季气旋中云的微物理特性与雷达和激光雷达对这些特性的探测之间的关系。模拟研究将确定模拟的降水子结构是否与冬季风暴系统中观测到的特征一致，并提供对这些子结构发生的过程的更好理解。因此，这些发现将直接应用于预测。教育部分由9所设有大气科学系的大学的学生参加，将对本科生和研究生教育以及为大气实地研究招募新科学家作出贡献。

The dynamic and microphysical processes that govern the spatial and temporal variability of precipitation within extratropical cyclones remain poorly understood. Variability in the location, type, and intensity of precipitation is often determined by precipitation banding and/or embedded convection, particularly in the northwest and warm frontal quadrant in cyclones where frontal structures and associated frontal circulations are modified by deformation flow. The Principal Investigators will execute a comprehensive field campaign and numerical modeling study that will address outstanding scientific questions targeted at improving understanding of precipitation substructures in the northwest and warm frontal quadrants of continental extratropical cyclones. In the course of this study the following questions will be addressed: 1) What are the predominant spatial patterns of organized precipitation substructures, such as bands and generating cells and how do they evolve? 2) How do frontal scale systems above and within the boundary layer such as warm fronts, trowals, cold fronts aloft, and occluded fronts relate to these precipitation substructures? 3) What are the thermodynamic and kinematic structures of these frontal systems including the distribution of moisture and vertical motion? 4) What instabilities and types of mesoscale forcing control the generation and evolution of precipitation substructures? 5) How do microphysical processes vary between the different precipitation substructures and what are the consequences? 6) Is instability triggered in ice-saturated ascent critical in some of these instances and is it through the release of the latent heat of deposition that instabilities can persist? The Principal Investigators will obtain and analyze detailed, high resolution observations of precipitation substructures using three mobile ground-based observing systems, the University of Alabama at Huntsville Mobile Integrated Profiling System, the Mobile Alabama X-band dual polarization radar, and the NSF/National Center for Atmospheric Research (NCAR) Mobile GPS Advanced Upper Air Sounding System, along with the NSF/NCAR C-130 Aircraft equipped with microphysical probes and the Wyoming Cloud Doppler Radar and Cloud Lidar. They will also simulate the precipitation substructures using the Weather Research and Forecasting Model at high horizontal and vertical resolution. The observations will provide the basis for the development of testable hypotheses that can be addressed systematically in the modeling studies. The field campaign (termed Profiling Of Winter Storms, or PlOWS) will have an education component, involving students from 9 universities with atmospheric science departments. Intellectual merit: The combined dynamical/microphysical observational strategy in conjunction with high resolution numerical modeling, will provide the basis for answering key scientific questions in a more complete and definitive way than heretofore possible. The new observational capabilities that will be applied in this research will provide fundamentally new information about the structure, dynamic and physical properties of these storms on scales never before observed. Broader impacts: Nationwide, nearly 7000 deaths, 600,000 injuries, and 1.4 million accidents per year are due to adverse road weather, mostly during winter, and costs associated with a single blizzard can range from $0.1M to $3.0B. The research will provide new insight concerning remote sensing of winter weather systems that can translate directly into better operational interpretation and observation strategies of winter weather mesoscale features. The research will contribute to a fundamental understanding of the relationship between the microphysical properties of clouds in winter cyclones and radar and lidar sensing of those properties. The modeling studies will determine if modeled precipitation substructures are consistent with observed features in winter storm systems and provide a better understanding of processes responsible for the occurrence of those substructures. Thus the findings will have direct application to forecasting. The education component, involving students from nine universities with atmospheric science departments, will contribute to undergraduate and graduate education and recruitment of new scientists into atmospheric field research.