Collaborative Research: Measurement and Analysis of Nocturnal Mesoscale Convective Systems and Their Stable Boundary Layer Environment During PECAN

平原夜间高空对流实验将研究夜间中尺度对流系统(MCSs)和对流的演变及其与不断演变的夜间稳定边界层(SBL)环境的相互作用。这项建议涉及山核桃的两个主要目标：1)描述从地面到夜间高空MCS结构的转变，以及由MCS产生的冷池与夜间SBL的相互作用，以及2)确定稳定的边界层、风的垂直廓线和夜间低空急流(NLLJ)上方的稳定性如何影响地面和高空MCS的组织和演变。为了纠正目前缺乏对夜间MCS及其SBL环境的详细、综合观测的情况，该项目将在山核桃期间利用移动地面雷达、移动探测系统和移动中子网与其他地面和机载观测平台协同观测夜间MCS和对流。多雷达综合、数据同化和模拟将提供对这些组合观测的综合分析，以评估夜间MCS的详细内部结构以及静力稳定性、预先存在的边界和风切变对夜间MCS演变过程的影响。智力优势：该项目强调通过多个移动多普勒和双极化雷达阵列以及移动探测和地面现场观测系统对夜间MCS及其SBL环境进行紧密协调观测。这些观测将被综合起来，以获得MCSs和新发起的对流及其环境的三维气流合成、降水场和热结构。移动雷达至关重要，因为它们可以提供更高的时间和空间分辨率以及对山核桃领域内任何区域的低空观测。C波段雷达需要具备穿透强降水和感知晴朗空气流入的能力。移动式C波段和X波段双极化雷达将提供超出WSR-88D极化雷达典型工作范围和低于基本扫描高度的微物理信息。流动探空和地面观测通过提供降水内外独特的浮力和切变廓线来补充雷达测风，从而解决了MCS内部的动力学问题，并描述了与MCSs相互作用的SBL环境。这些数据与来自固定和移动的地面雷达、剖面仪、中子网和飞机的其他山核桃数据相结合，对于解释MCS相对于现场环境条件的夜间演变以及为MCS的云动力-微物理模式模拟提供输入和验证是必不可少的。该项目的科学目标是：(I)记录夜间MCS和对流的内部结构和演变；(Ii)建立控制夜间MCS演变的环境成分和相关物理机制；以及(Iii)在详细的云分辨模式中检验关于MCS动态微物理强迫和MCS与环境相互作用的假设。在这里进行的研究将促进对MCS内部动力学以及与SBL相互作用的基本知识，并将使两者在云解析模式中得到更好的表示。广泛的影响：表征夜间MCS的形态以及冷池对流区前方和附近的温度、湿度和风的垂直廓线对于提高对恶劣天气、暴雨、山洪和飞机结冰条件的地理范围和持续时间的诊断和短期预测的特异性和准确性至关重要。此外，这些山核桃现场观测对于完善数据同化系统和改善未来夜间MCS及其SBL环境的业务数值预报将是必不可少的。这里收集的数据集也将用于大学课堂到研究生水平。几名本科生和研究生将通过融入数据收集和场后阶段分析，接受执行大型大气场战役的培训。最后，这里收集的数据将提供给其他NSF和NOAA调查人员，这些调查人员被确定为山核桃项目的一部分。

The Plains Elevated Convection At Night (PECAN) experiment will investigate the evolution of nocturnal mesoscale convective systems (MCSs) and convection and their interactions with the evolving nocturnal stable boundary layer (SBL) environment. This proposal addresses two primary goals of PECAN: 1) To characterize the transition from surface-based to elevated nocturnal MCS structure and the interaction of cold pools generated by MCSs with the nocturnal SBL, and 2) to determine how the organization and evolution of surface-based and elevated MCSs are influenced by the stable boundary layer and the vertical profile of wind and stability above the nocturnal low-level jet (NLLJ). To rectify the present paucity of detailed, integrated observations of nocturnal MCSs and their SBL environments, the project will observe nocturnal MCSs and convection with mobile ground-based radars, mobile sounding systems, and mobile mesonets in concert with other ground-based and airborne observing platforms during PECAN. Multi-radar syntheses, data assimilation, and modeling will provide the integrated analyses of these combined observations to evaluate the detailed internal structure of nocturnal MCSs and the impact of static stability, pre-existing boundaries, and wind shear on nocturnal MCS evolution processes.Intellectual Merit:This project emphasizes the tightly coordinated observation of nocturnal MCSs and their SBL environments with an array of multiple mobile Doppler and dual-polarimetric radars in conjunction with mobile soundings and surface in situ observing systems. These observations will be integrated to obtain 3-D airflow syntheses, precipitation fields, and thermal structure of MCSs and newly initiated convection and their environments. Mobile radars are essential as they can provide enhanced temporal and spatial resolution and low-level observations over any area within the PECAN domain. C-band radars, with their ability to both penetrate heavy precipitation and sense clear-air inflow, are required. The mobile C- and X-band dual-polarimetric radars will provide microphysical information beyond the typical operating ranges and below base-scan altitudes of the polarimetric WSR-88D radars. The mobile sounding and surface observations complement the radar wind measurements by providing unique buoyancy and shear profiles both within and outside of precipitation, thus resolving internal MCS dynamics and characterizing the SBL environment that interacts with the MCSs. These data, in combination with other PECAN data from fixed and mobile ground-based radar, profilers, mesonets, and aircraft, are essential for interpreting nocturnal MCS evolution with respect to in situ environmental conditions and for providing input and validation of cloud dynamical-microphysical model simulations of MCSs. The scientific objectives of this project are to: (i) document the internal structure and evolution of nocturnal MCSs and convection; (ii) establish the environmental ingredients and related physical mechanisms that control nocturnal MCS evolution; and (iii) test hypotheses concerning MCS dynamical microphysical forcing and MCS-environment interactions within detailed cloud-resolving models. The research conducted here will advance fundamental knowledge of the internal MCS dynamics and interactions with the SBL and will enable better representations of both within cloud-resolving models.Broader Impacts:Characterizing the morphology of nocturnal MCSs and the vertical profiles of temperature, humidity and winds ahead of and near the convective region in the cold pool are essential to helping improve the specificity and accuracy of diagnoses and short-term predictions of the geographical extent and duration of severe weather, heavy rainfall, flash flooding, and aircraft icing conditions. Additionally, these PECAN field observations will be essential for refining data assimilation systems and improving future operational numerical predictions of nocturnal MCSs and their SBL environments. The datasets collected here will also be used in university classes through graduate level. Several undergraduate and graduate students will be trained in the execution of a large atmospheric field campaign by being integrated into the data collection and post-field phase analysis. Lastly, the data collected here will be made available to other NSF and NOAA investigators identified as part of the PECAN project.