Comparing reactions to two severe tornadoes in one Oklahoma community

The authors compared the effect of the 3 May 1999 F5 and 8 May 2003 F3 tornadoes on the community of Moore, Oklahoma, by canvassing damaged areas after both tornadoes and surveying residents. Significantly more 1999 than 2003 residents reported property damage and injuries. Television and tornado sirens were the most common warnings each year, however, more 1999 residents received and responded to television warnings. Importantly, storm shelters were used more frequently in 2003. Fifty-one per cent of residents who experienced both tornadoes took the same amount of protective action in 2003 as they had in 1999; 22% took less; and 27% took more. Residents who took less action said that the reason for doing so was inadequate warning and shelter. First-hand experience of tornadoes prompts people to heed warnings when adequate notification is received and to take effective protective action when adequate shelter is available.     

无上部抽吸装置储罐区人工龙卷风风场模拟

为了减少因储罐泄漏位置不确定造成的人员伤亡,指导应急疏散,提出利用人工龙卷风定向控制气体流动方向的模型。首先基于Fluent软件建立了储罐区域人工龙卷风数值模型,分析切向速度和压强沿径向变化规律,发现与经典Rankine涡模型切向速度沿径向分布规律一致,证实可在储罐区以射流相切的方式形成人工龙卷风风场。其次研究了涡流比和进风量对风场控制气流特性的影响,即分析形成的龙卷风风场最大切向速度、压强差变化规律,结果表明,涡流比越大,形成的龙卷风风场中切向速度和压强差越小,即气流向中心汇聚能力越弱;进风量越大,形成的龙卷风风场中切向速度和压强差越大,即气流向中心汇聚能力越强。研究表明,用人工龙卷风控制储罐泄漏气流方向是可行的。     

Normalized tornado damage in the United States: 1950–2011

In 2011, thunderstorms in the United States resulted in 550 deaths from tornadoes and more than $28 billion in property damage, according to data from the US National Oceanic and Atmospheric Administration, with the vast majority of economic losses resulting from tornadoes. This article normalizes U.S. tornado damage from 1950 to 2011, using several methods. A normalization provides an estimate of the damage that would occur if past events occurred under a common base year's societal conditions. We normalize for changes in inflation and wealth at the national level and changes in population, income and housing units at the county level. Under several methods, there has been a sharp decline in tornado damage. This decline corresponds with a decline in the reported frequency of the most intense (and thus most damaging) tornadoes since 1950. However, quantification of trends in tornado incidence is made difficult due to discontinuities in the reporting of events over time. The normalized damage results are suggestive that some part of this decline may reflect actual changes in tornado incidence, beyond changes in reporting practices. In historical context, 2011 stands out as one of the most damaging years of the past 61 years and provides an indication that maximum damage levels have the potential to increase should societal change lead to increasing exposure of wealth and property.     

Facebook and Twitter,communication and shelter,and the 2011 Tuscaloosa tornado

This paper represents one of the first attempts to analyse the many ways in which Facebook and Twitter were used during a tornado disaster. Comparisons between five randomly selected campus samples and a city of Tuscaloosa, Alabama, sample revealed that campus samples used Facebook and Twitter significantly more both before and after the tornado, but Facebook usage was not significantly different after the event. Furthermore, differences in social media usage and other forms of communication before the tornado were found for age, education, and years lived in Tuscaloosa. Generally, age and education were inversely proportionate to social media usage. Influences on shelter‐seeking actions varied between social media users and three random samples of non‐social media users; however, it appears that social media respondents were likely to be using a smartphone simultaneously to access warning polygon information, to receive text message alerts, and to listen or respond to environmental cues.     

Epidemiology of tornado destruction in rural northern Bangladesh: risk factors for death and injury

The epidemiology of tornado-related disasters in the developing world is poorly understood. An August 2005 post-tornado cohort study in rural Bangladesh identified elevated levels of death and injury among the elderly (≥ 60 years of age) (adjusted odds ratio (AOR) = 8.9 (95 per cent confidence interval (CI): 3.9-20.2) and AOR = 1.6 (95 per cent CI: 1.4-1.8), respectively), as compared to 15-24 year-olds, and among those outdoors versus indoors during the tornado (AOR = 10.4 (95 per cent CI: 5.5-19.9) and AOR = 6.6 (95 per cent CI: 5.8-7.5), respectively). Females were 1.24 times (95 per cent CI: 1.15-1.33) more likely to be injured than males. Elevated risk of injury was significantly associated with structural damage to the house and tin construction materials. Seeking treatment was protective against death among the injured, odds ratio = 0.08 (95 per cent CI: 0.03-0.21). Further research is needed to develop injury prevention strategies and to address disparities in risk between age groups and between men and women.     

Individual relocation decisions after tornadoes: a multi‐level analysis

This study examines how multi‐level factors affected individuals' relocation decisions after EF4 and EF5 (Enhanced Fujita Tornado Intensity Scale) tornadoes struck the United States in 2013. A telephone survey was conducted with 536 respondents, including oversampled older adults, one year after these two disaster events. Respondents' addresses were used to associate individual information with block group‐level variables recorded by the American Community Survey. Logistic regression revealed that residential damage and homeownership are important predictors of relocation. There was also significant interaction between these two variables, indicating less difference between homeowners and renters at higher damage levels. Homeownership diminished the likelihood of relocation among younger respondents. Random effects logistic regression found that the percentage of homeownership and of higher income households in the community buffered the effect of damage on relocation; the percentage of older adults reduced the likelihood of this group relocating. The findings are assessed from the standpoint of age difference, policy implications, and social capital and vulnerability.     

旋激技术研究

仿效龙卷风 ,独创了旋激技术 ,研制开发出了一种龙卷风废气净化塔。该塔结构精简 ,净化效率高 ,脱水好 ,阻力小 ,节水节能 ,运行稳定可靠。首次在长沙摩托车厂锅炉烟气除尘脱硫示范工程中得到了应用 ,效果良好。     

Predictors of compliance with tornado warnings issued in Joplin,Missouri, in 2011

Joplin, a city in the southwest corner of Missouri, United States, suffered an EF‐5 tornado in the late afternoon of 22 May 2011. This event, which claimed the lives of 162 people, represents the deadliest single tornado to strike the US since modern record‐keeping began in 1950. This study examines the factors associated with responses to tornado warnings. Based on a post‐tornado survey of survivors in Joplin, it reveals that tornado warnings were adequate and timely. Multivariate logistic regression identified four statistically significant determinants of compliance with tornado warnings: number of warning sources, whether respondents were at home when the tornado struck, past tornado experience, and gender. The findings suggest several recommendations, the implementation of which will further improve responses to tornado warnings.     

龙卷风风灾的调查与评估

以江苏省为例搜集并核实了最近３７年间龙卷风的事实和灾情资料，尝试性地采用专家评分方式从风灾实况对各次龙卷风的强度进行了富士达级别评定，论证了这种从具有模糊性的灾情事实中提取半定量信息方法的客观性。结果发现，各强度级别是龙卷风的累积分布可近似用两段指数函数拟合。在此基础上，定量地给出了江苏省龙卷风频率和强度的地域分布，各级龙卷风的平均再现间隔年数等统计指标。     

2019年辽宁开原龙卷风观测事实分析

利用加密自动站、FY-4A卫星及多普勒雷达等观测资料,对2019年7月3日辽宁开原突发龙卷天气进行分析.结果表明:在冷涡减弱阶段,中纬度冷空气活动频繁,冷涡底部500 hPa与850 hPa的短波槽垂直分布,利于辽宁北部对流不稳定加强.FY-4A可见光云图显示,开原龙卷生消迅速,有明显的上冲云顶.雷达反射率因子特征是,...