Collaborative Research: Mesoscale Airmasses with High Theta-E (MAHTE)

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。强雷暴通常与炎热潮湿的气团有关。然而，有证据表明，在某些情况下，风暴可以在边界较冷的一侧保持甚至增强。这项研究项目将分析这些情景，在这些情景中，气团的凉爽一侧有大量可用于为雷暴提供燃料的能量。研究人员将开发病例气候学，并分析导致病例发展的物理过程。这项研究通过改进对恶劣天气事件的预测，对公共安全产生了直接影响。多名学生将参与该项目，以确保培养下一代科学家。研究小组将对具有高theta-e(MAHTE)的中尺度气团进行研究，MAHTE通常是位于锋面或外流边界凉爽一侧的潮湿空气区域，具有高对流可用势能值(CAPE)。该奖项是对MAHTE的基础性研究，以确定它们的气候学和导致它们发展的物理过程。对地面观测的分析将提供美国境内MAHTE的空间分布、日循环和季节性。理想化的模拟将被用来提供对MAHTE发展过程的透彻理解。将检验以下假设：1)MAHTE发展的主要机制是穿过气团边界的垂直差异平流，2)MAHTE发展的次要机制是MAHTE前缘附近表面水汽通量的局部增强，以及3)MAHTE的形成可能取决于环境风切变。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Severe thunderstorms are commonly associated with hot and humid airmasses. However, there is evidence that storms can be maintained or even enhanced on the cooler side of a boundary in certain circumstances. This research project will analyze these scenarios, where the cool side of an airmass has significant energy available to fuel thunderstorms. The researchers will develop a climatology of cases and analyze the physical processes responsible for their development. The research has direct impact on public safety through improved forecasting of severe weather events. Multiple students would be involved in the project, ensuring training of the next generation of scientists.The research team will conduct a study of mesoscale airmasses with high theta-e (MAHTE), which are generally areas of moist air with high Convective Available Potential Energy (CAPE) values on the cool side of a frontal or outflow boundary. This award is for a foundational study on MAHTEs to determine their climatology and the physical processes responsible for their development. Analysis of surface observations will provide the spatial distribution, diurnal cycle, and seasonality of MAHTEs within the US. Idealized simulations would be used to provide a thorough understanding of the processes through which MAHTE develop. The following hypotheses will be tested: 1) The primary mechanism through which MAHTE develop is differential vertical advection across the airmass boundary, 2) A secondary mechanism through which MAHTEs develop is locally-enhanced surface fluxes of moisture near the leading edge of the MAHTEs, and 3) MAHTE formation is likely to depend on the environmental wind shear.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.