Identifying the Physical Drivers and Radar Signatures of Fire-Generated Tornadic Vortices

野火可以产生自己的恶劣天气，包括龙卷风和雷暴嵌入野火羽。这些火灾产生的极端威胁消防员和公共安全，但知之甚少，往往无法预测。为了填补这一知识空白，研究人员建议通过从天气雷达和卫星数据中识别导致火灾产生的龙卷风和雷暴的共同因素来了解火灾产生的极端天气。该项目还将让公众参与野火科学，例如开发专注于火灾产生的天气的中学课堂课程，并开展公民科学社交媒体活动，收集野火羽流“雨”下的灰烬和碎片的照片。由公众收集的众包数据将有助于提高我们对野火羽流的理解，以便更好地记录飞入天空的物质的大小和形状。这项拟议的工作的动机是几十年来成功地使用雷达和卫星观测来发布对流恶劣天气的救生警报（例如，强雷暴）。对于火灾产生的龙卷风涡（FGTV）和pyrocumulonimbus（pyroCb），这些相同的工具显示出显着的，但不完全实现的潜力。为了充分实现这一潜力，需要新的物理和概念模型来解释野火环境的雷达和卫星观测。为了开发这些模型，研究人员将测试一系列假设，这些假设旨在隔离与FGTV开发相关的雷达和卫星观测到的火灾和羽流过程的共同特征。这些假设是基于初步观察，表明FGTV产生的火灾通常表现出：（1）具有嵌入和脱落涡的分叉和分叉羽流，（2）火灾周围的流动分裂和流动逆转的不对称性，有利于涡旋转的一种感觉（即，气旋与反气旋），和（3）pyroCb的启动与涡增强的同时。在分离FGTV火灾的共同属性和观察到的特征时，研究小组的目标是为FGTV形成产生概念模型。这些概念模型将促进救生警报，并加强对野火利益相关者的决策支持，从而提供直接的社会效益。作为本提案一部分的社区参与和教育将包括：（a）社交媒体公民科学运动，将雷达观测与野火羽流落下的灰烬大小和形状的照片记录联系起来，（B）课堂中学学习经验和课程，加上基于应用程序的数据收集模块，（c）研究生辅导和课程开发，以及（d）向公众和野火利益攸关方进行宣传。公民科学活动预计每年将达到1000名用户，课堂计划每年将超过500名学生。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Wildfires can generate their own severe weather, including tornados and thunderstorms embedded in the wildfire plume. These fire-generated extremes threaten fire-fighter and public safety yet are poorly understood and often unpredicted. To fill this knowledge gap, the investigators propose to understand fire-generated extreme weather by identifying the common factors contributing fire-generated tornados and thunderstorms from weather radar and satellite data. The project will also engage the public in wildfire science such as developing middle-school in-class lessons focused on fire-generated weather and conducting a citizen-science social-media campaign to collect photographs of the ash and debris that “rain” down from wildfire plumes. The crowd-sourced data collected by the public will help improve our understanding of wildfire plumes for better documenting the size and shape of material lofted into the sky.The proposed work is motivated by decades of success in using radar and satellite observations to issue life-saving warnings for convectional severe weather (e.g., severe thunderstorms). For fire-generated tornadic vortices (FGTV) and pyrocumulonimbus (pyroCb) these same tools show remarkable, yet incompletely realized potential. To fully realize this potential, new physical and conceptual models are required for interpreting radar and satellite observations of the wildfire environment. To develop these models, the investigators will test a sequence of hypotheses designed to isolate the common characteristics of radar and satellite observed fire and plume processes linked to the FGTV development. These hypotheses are based on preliminary observations demonstrating FGTV producing fires often exhibit: (1) bent-over and bifurcating plumes with both embedded and shedding vortices, (2) asymmetries in flow splitting and flow reversal around the fire that favor one sense of vortex rotation (i.e., cyclonic vs. anticyclonic), and (3) pyroCb initiation concurrent with vortex intensification. In isolating the common attributes and observed signatures of FGTV fires, the research team aims to produce conceptual models for FGTV formation. These conceptual models will facilitate life-saving warnings and enhance decision support for wildfire stakeholders, thereby providing an immediate societal benefit. Community engagement and education as part of this proposal will include: (a) social-media citizen-science campaign linking radar observations with photographic documentation of size and shape of ash falling from wildfire plumes, (b) in-classroom middle school learning experiences and curriculum coupled with an app-based data collection module, (c) graduate student mentoring and curriculum development, and (d) outreach to the public and wildfire stakeholders. The citizen-science campaign is expected to reach 1000s of users annually, and the in-classroom program upwards of 500 students per year.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.