The Carr Fire Vortex: A Case of Pyrotornadogenesis?
The Carr Fire Vortex: A Case of Pyrotornadogenesis?
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DOI：
10.1029/2018gl080667
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发表时间：
2018-12-16
影响因子：
5.2
通讯作者：
Abatzoglou, J. T.
中科院分区：
文献类型：
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作者：
Lareau, N. P.;Nauslar, N. J.;Abatzoglou, J. T.
雷达和卫星观测记录了2018年7月26日在加州雷丁附近的卡尔火灾期间破坏性火灾产生的漩涡的演变。美国国家气象局估计，气旋的表面风速超过每秒64米，相当于EF-3级龙卷风。雷达数据显示，形成的涡流的气旋风切变沿着火周边的先行区域内，并立即快速垂直发展的对流羽流，从6到12 kmaloft在短短15分钟。快速羽流发展与释放的潮湿不稳定的pyrocumulonimbus（pyroCb）。随着云层的增长，漩涡增强并上升，最终达到5,200米的高度。这一事件与其他火灾产生的涡旋不同，并表明其与非中气旋龙卷风的动力学相似性。简明语言摘要2018年7月26日，卡尔大火期间，一场龙卷风强度的火灾产生的涡旋摧毁了加州雷丁的部分地区。在这项研究中，卫星和雷达观测记录了涡旋的演变，揭示了与龙卷风动力学的相似之处。漩涡形成的一个关键因素是火产生的冰顶云的发展（即，一个pyrocumulonimbus），达到高达12公里的高空。云层的发展有助于拉伸底层的空气柱，从而将旋转集中在地表附近，并导致龙卷风强度的风速，估计约为64米/秒。这些观测结果将有助于预报员和科学家识别，并可能警告未来破坏性的火灾产生的漩涡。
Radar and satellite observations document the evolution of a destructive fire-generated vortex during the Carr fire on 26 July 2018 near Redding, California. The National Weather Service estimated that surface wind speeds in the vortex were in excess of 64 m/s, equivalent to an EF-3 tornado. Radar data show that the vortex formed within an antecedent region of cyclonic wind shear along the fire perimeter and immediately following rapid vertical development of the convective plume, which grew from 6 to 12 kmaloft in just 15 min. The rapid plume development was linked to the release of moist instability in a pyrocumulonimbus (pyroCb). As the cloud grew, the vortex intensified and ascended, eventually reaching an altitude of 5,200 m. The role of the pyroCb in concentrating near-surface vorticity distinguishes this event from other fire-generated vortices and suggests dynamical similarities to nonmesocyclonic tornadoes.Plain Language Summary A tornado-strength fire-generated vortex devastated portions of Redding, California, during the Carr fire on 26 July 2018. In this study, satellite and radar observations document the evolution of the vortex, revealing similarities to tornado dynamics. A key factor in the vortex formation was the development of a fire-generated ice-topped cloud (i.e., a pyrocumulonimbus), which reached as high as 12 km aloft. The development of the cloud helped stretch the underlying column of air, thereby concentrating the rotation near the surface and causing the tornado strength winds, estimated at similar to 64 m/s. These observations will help forecasters and scientists identify, and potentially warn for, future destructive fire-generated vortices.