Storm-environment interactions controlling the probability of supercell tornadogenesis

这个项目的目标是提高我们对为什么一些超级单体（旋转雷暴）会产生龙卷风，而其他在非常相似的大气条件下形成的超级单体不会产生龙卷风的理解。已知导致龙卷风形成（与失败）的特定过程链对环境和风暴本身中看似微小的细节高度敏感。 虽然近几十年来我们的社区在预测龙卷风方面取得了实质性的进展，但我们还没有解释为什么龙卷风如此频繁地无法在看似有利的大气条件下形成。这项研究的具体目的是更好地了解龙卷风形成中的这些故障点。 如果没有这样的进展，预测和及时发出龙卷风警报（并避免误报）的能力不太可能进一步提高。该项目的主要科学家将邀请来自不同背景的学生和国家气象局的天气预报员参与这项研究。预期的结果将提高我们对龙卷风如何形成的基本理解，并导致公共预报和警报的改进。研究人员试图通过假设驱动的研究来推进我们对超级单体和龙卷风形成的基础科学知识。拟议的工作将直接比较龙卷风和非龙卷风超级细胞的属性与计算机建模技术的层次结构，包括模拟的大型合奏，并结合新的技术来模拟随时间变化的环境。拟议的工作还将量化环境（风暴外部）与风暴内部过程在超级单体龙卷风形成中的作用。 最后，建议的工作将解释的前兆（在风暴形成之前）负责生成的有利环境条件的龙卷风（特别是，大气风廓线非常接近地面）。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

The goal of this project is to improve our understanding of why some supercells (rotating thunderstorms) produce tornadoes and others that form in very similar atmospheric conditions do not. The specific chain of processes that result in tornado formation (vs. failure) are known to be highly sensitive to seemingly minor details within the environment and the storm itself. While our community has made substantial progress at forecasting tornadoes in recent decades, we have yet to explain why tornadoes so frequently fail to form within seemingly favorable atmospheric conditions. The specific aim of this research is to understand better these failure points in tornado formation. Without such progress, the ability to forecast and produce timely warnings for tornadoes (and avoid false alarms) is unlikely to further improve. The leading scientists for this project will involve students from diverse background and weather forecasters from the National Weather Service in this research. The expected outcome would improve our basic understanding of how tornadoes form and lead to improvements in public forecasts and warnings.The investigators seek to advance our fundamental scientific knowledge of supercells and tornado formation through hypothesis-driven research. The proposed work will directly compare the attributes of tornadic and nontornadic supercells with a hierarchy of computer modeling techniques, including large ensembles of simulations and incorporating novel techniques to emulate environments that vary in time. The proposed work will also quantify the roles of environmental (external to the storm) vs. within-storm processes in supercell tornado formation. Finally, the proposed work will explain the precursors (prior to storm formation) responsible for the generation of favorable environmental conditions for tornadoes (specifically, the atmospheric wind profile very near the ground).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.