Investigation of serious tornado damage in Saroma-cho, Hokkaido

北海道佐吕间町严重龙卷风灾害调查

• 批准号: 18900003
• 负责人: TAMURA Yukio
• 金额: --
• 依托单位: Tokyo Polytechnic University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Special Purpose
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18900003/
• 关键词: tornado; supercell; Doppler radar; numerical cloud resolving storm simulator; mesocvclone; gust damage; windborne debris; questionnaire survy

An investigation was carried out of a tornado and damage caused on November 7, 2006 in Hokkaido, Saroma-cho from both meteorological and a engineering viewpoints. The following points were clarified. The cumulonimbus that brought the tornado was about 10 km high and 20 to 30 km in diameter. It had typical supercell characteristics, i.e., a pair of a strong up and down draft regions and the vault and embryo curtain. The foehn phenomenon had been caused by wind from the south flowing over mountains. This phenomenon greatly affected the generation of the tornado. A complex geometrical feature around the site was another factor in the tornado's generation. A technique using Doppler radar data and numerical cloud resolving storm simulator was applied to a short-period tornado forecast. Applying horizontal wind speeds and the mixing ratio of rain obtained by dual Doppler radar analysis improved the estimation.A detailed investigation of damage to buildings showed that the damaged area was about 1 km long and about 100 to 250 m wide. Most of the debris was scattered in the northern area of Iwasa district, while some flew more than 20 km, reaching the Okhotsk-sea. A questionnaire survey was circulated to 151 families throughout the damaged area. From the primary result of the questionnaire, relations between dam age and structure of houses, meteorological phenomena under the tornado, people's behaviors and government actions were studied. There was considerable damage to houses due to the impact of flying debris, and some roofs were blown off. The standard spec and method for inspecting the exterior cladding materials damaged by flying debris were surveyed. The results should be valuable for further evaluation of countermeasures to tornados.

从气象和工程两个角度对2006年11月7日发生在北海道的一次龙卷风及其造成的损失进行了调查。澄清了以下几点。带来龙卷风的积雨云高约10公里，直径约20至30公里。它具有典型的超细胞特征，即一对强烈的上下牵引区和穹隆和胚胎窗帘。福恩现象是由从南方吹来的风吹过山脉造成的。这一现象极大地影响了龙卷风的生成。现场周围复杂的几何特征是龙卷风生成的另一个因素。利用多普勒雷达资料和数值云分辨风暴模拟器，对一次短周期龙卷风预报进行了研究。应用水平风速和双多普勒雷达分析得到的降雨混合比改进了估计。对建筑物破坏的详细调查显示，受损区域长约1公里，宽约100至250米。大部分残骸散落在岩萨区北部地区，一些残骸飞行了20多公里，到达鄂霍次克海。一份问卷调查已分发给受灾地区的151户家庭。根据问卷调查的初步结果，研究了坝龄与房屋结构、龙卷风下的气象现象、人们的行为和政府行为的关系。飞来的碎片对房屋造成了相当大的破坏，一些屋顶被吹走。综述了飞片破损外包层材料检验的标准规范和方法。研究结果对进一步评估应对龙卷风的对策具有参考价值。