Collaborative Research: Development of Unmanned Aircraft System for Research in a Severe Storm Environment and Deployment within the VORTEX 2

该项目的目的是开发和利用无人机系统(UAS)在超级单体雷暴的后翼区域获得高空的关键气象观测。这是一个试点项目，最初的重点是系统开发和在严重风暴环境中利用这类系统的经验。如果试行项目成功，首席调查员打算参加第二次龙卷风旋转起源核查实验(涡旋2)。调查人员将利用科罗拉多大学在无人驾驶飞机运营方面的专业知识，开发一种足够安全的系统，以获得联邦航空管理局的运营授权证书。观测将被用来评估与超级单体上升气流后部的斜压涡度产生有关的具体假设，以及随后将该涡度重新定向为观测到的反向旋转的低层涡旋。这一对的气旋性成员往往是先行的龙卷风涡旋。智力价值超级细胞龙卷风的发生是一系列复杂过程的结果。有证据表明，龙卷风中的涡度起源于超级单体上升气流和后方下降气流(RFD)之间的水平涡度。反过来，RFD似乎部分是超级单体特有的小尺度降水结构的结果：钩状回波和/或一个狭窄的下降反射率核心。在一些超级单体中，主要垂直气流之间产生的涡度在上升气流中向上拉升，导致后翼阵风锋汇合区出现拱形涡线和相关的反旋转涡旋。在某些条件下，似乎受负浮力的影响，龙卷风可能发生在对转对的气旋成员附近。更广泛的影响这项工作的一个重要目标是，它将有助于开发可快速部署的中尺度和风暴尺度的无人驾驶飞机传感系统。该系统将经过适当的设计，以极大地减少未来部署的监管障碍。将在技术和监管问题上获得重要知识，使未来能够部署用于天气研究的无人机。收集到的观测将提高对RFD浮力和龙卷风成因的了解。这一信息可通过利用具有双极化分集能力的多普勒雷达对后侧降水形态和水流星结构进行诊断，从而改进龙卷风预警过程。此外，预计可以通过低层热力学层结的知识来估计RFD浮力。最终，业务气象学家可能会更好地区分潜在的龙卷风超级单体和非龙卷风超级单体。

The purpose of this project is to develop and utilize unmanned aircraft systems (UAS) to obtain critical meteorological observations aloft in the rear flank region of supercell thunderstorms. This is a pilot project with the initial emphasis being on the system development and obtaining experience in utilizing such systems in severe storm environments. If the pilot development project is successful, the Principal Investigators intend to participate in the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX 2). The investigators will utilize the expertise in unmanned aircraft operations of the University of Colorado to develop a system that is sufficiently safe to obtain a Certificate of Authorization for operation from the Federal Aviation Administration. Observations will be used to evaluate specific hypotheses related to the baroclinic generation of vorticity at the rear of the supercell updraft, and subsequent reorientation of that vorticity into the observed counter-rotating low-level vortices. The cyclonic member of this pair appears often to be the antecedent tornadic vortex. Intellectual Merit Supercell tornadogenesis is the result of a complex series of processes. Evidence suggests that the vorticity in a tornado originates as horizontal vorticity between the supercell updraft and a trailing rear flank downdraft (RFD). The RFD, in turn, appears to be partially the result of small-scale precipitation structures unique to supercells: the hook echo and/or a narrow descending reflectivity core. In some supercells, the vorticity generated between the major vertical drafts is drawn upward in the updraft, leading to arched vortex lines and associated counter-rotating vortices in the rear flank gust front convergence zone. Under certain conditions, that appear to be governed by the degree of negative buoyancy in the RFD, tornadogenesis can occur in the vicinity of the cyclonic member of the counter-rotating pair. Broader Impacts An important goal of this work is that it will contribute to the development of a rapidly-deployable mesoscale and stormscale UAS sensing system. The system will be suitably designed to greatly reduce regulatory hurdles to its future deployment. Important knowledge will be gained on technical and regulatory issues that will allow future deployments of UAS for weather research. Collected observations will improve understanding of RFD buoyancy and tornado cyclone genesis. This information may lead to improvements in the tornado warning process via the diagnosis of rear-flank precipitation morphology and hydrometeor structure using Doppler radars with dual-polarization diversity capability. Further, it is anticipated that RFD buoyancy can be estimated through knowledge of the low-level thermodynamic stratification. Eventually, it is likely that operational meteorologists can make much better discriminations between potentially tornadic and non-tornadic supercells.