VORTEX2: Multiscale Analyses of Tornadic Storms Using Multiparameter Mobile Radars

智力优点：验证龙卷风实验2（VORTEX 2）中的旋转起源是对导致龙卷风发生的因素的多尺度调查。 VORTEX 2是VORTEX 1的后续，其现场阶段在1994年和1995年春季进行。 涡1先进的知识龙卷风和非龙卷风风暴的运动学结构，并提供了一些线索，超级单体风暴和龙卷风的演变非常精细的空间尺度异质性的敏感性。 VORTEX 2社区打算扩展并建立在VORTEX 1的结果之上。该提案支持的研究涉及风暴尺度环流以及影响龙卷风风暴中涡度发展和分布的热力学和降水变率。 这些研究目标共有的主要数据集是对母体龙卷风风暴及其周围环境的整个宽度和深度的多普勒和偏振雷达观测。 需要C波段雷达，因为它们既能穿透强降水，又能探测与超级单体风暴有关的晴空气流。 虽然主要研究人员将用两个C波段覆盖风暴的整个深度，但将用X波段双极化雷达对最低3公里进行频繁的协调采样，以检查中气旋下方后翼下沉气流和角动量的微观物理和动力学。 这三个雷达将密切协调，以提供风暴尺度环流和降水结构，将其他仪器的更精细尺度观测置于更大尺度风暴和环境流的背景下。本研究的科学目标是研究：（i）与超级单体中低层旋转相关的涡度动力学，（ii）角动量转移对龙卷风形成的作用，（iii）后翼下沉气流的降水和热力学，（iv）环境异质性的影响（包括边界）对风暴演变的影响，（v）单元合并对龙卷风发生的作用，（vi）龙卷风和非龙卷风超级单元内极化特征的演变，以及（vii）通过使用集合卡尔曼滤波数据同化改进龙卷风风暴的分析和预报。更广泛的影响：根据1997年关于天气的社会和经济影响的研讨会，龙卷风风暴每年造成约73人死亡，平均经济影响约为7亿美元。 虽然与龙卷风警报相关的前置时间随着国家气象局（NWS）多普勒现代化和预报员培训计划而增加，但误报率基本保持不变。 在误报方面缺乏改进反映了对可能导致或限制龙卷风发生的物理过程缺乏了解。 在这里进行的研究将提高基础知识，使更好的概念模型和提高预测能力。 改进的数据同化和数值天气预报技术将有助于预报员更好地向公众发出警告。 独立的双极化和多多普勒风场将有助于风暴过程和模式验证研究。 双极化数据将提供与龙卷风发生相关的极化特征的早期指示，如果它们存在的话，这将最大限度地提高NWS业务雷达网络的双极化升级的效益。这些数据集也将用于大学课程，从新生入学到研究生水平的学期项目。 将开发并向社区提供基于计算机的教学模块。

Intellectual merit: The Verification of Origins of Rotation in Tornadoes Experiment #2 (VORTEX 2) is a multi-scale investigation of factors that lead to tornadogenesis. VORTEX 2 is a follow on to VORTEX 1 whose field phase was conducted during the Spring of 1994 and 1995. The VORTEX 1 advanced knowledge of the kinematic structures of tornadic and nontornadic storms and provided some hints as to the sensitivity of the evolution of supercell storms and tornadogenesis to very fine spatial scale heterogeneity. The VORTEX 2 community intends to extend and build upon the results of VORTEX 1. The research supported under this proposal addresses the stormscale circulations, and thermodynamic and precipitation variability that affect the development and distribution of vorticity in tornadic storms. The primary data set common to these research objectives are Doppler and polarimetric radar observations over the entire breadth and depth of the parent tornadic storm and its immediate environment. C-band radars, with their ability to both penetrate heavy precipitation and sense the clear-air inflow associated with supercell storms, are required. Although the Principal Investigators will cover the entire depth of the storm with two C-bands, frequent coordinated sampling of the lowest 3 kilometers will be made with a X-band dual-polarimetric radar to examine the microphysics and dynamics of the rear-flank downdraft and angular momentum beneath the mesocyclone. These three radars will be tightly coordinated to provide the storm-scale circulation and precipitation structure needed to place finer-scale observations from other instruments into the context of larger-scale storm and environmental flow. The scientific objectives of this research are to study: (i) vorticity dynamics associated with low-level rotation in supercells, (ii) the role of angular momentum transfer on tornadogenesis (iii) precipitation and thermodynamics of the rear-flank downdraft, (iv) the impact of environmental heterogeneity (including boundaries) on storm evolution, (v) the role of cell mergers on tornadogenesis, (vi) the evolution of polarimetric signatures within tornadic and non-tornadic supercells, and (vii) improvements in the analysis and forecasting of tornadic storms through the use of ensemble Kalman-filtering data assimilation. Broader impacts: According to the 1997 Workshop on Societal and Economic Impacts of Weather, tornadic storms account for about 73 fatalities each year and have an average economic impact of about $700M. While lead times associated with tornado warnings have increased with the National Weather Service (NWS) Doppler modernization and forecaster training program, false alarm rates have essentially remained flat. The lack of improvement in false alarms reflects lack of understanding of the physical processes that can cause or limit tornadogenesis. The research conducted here will improve fundamental knowledge, enabling better conceptual models and improved forecasting ability. The improved data assimilation and numerical weather prediction techniques will aid forecasters in their efforts to better warn the public. The independent dual-polarization and multiple-Doppler derived wind fields will aid in storm process and model validation studies. The dual-polarization data will provide an early indication of polarimetric signatures associated with tornadogenesis, if they exist, which will maximize the benefit of the dual-polarimetric upgrade of the NWS operational radar network. The datasets will also be used in university classes from freshman orientation to graduate level term projects. Computer-based teaching modules will be developed and made available to the community.