Vulnerability of families and households to natural hazards: A case study of storm surge flooding in Sarasota County,Florida

The role that family and household structure, size, and ethnic/racial composition play in increasing or decreasing vulnerability to natural hazards, which has been missing from the literature, is investigated. The study first reviews the conceptual foundations of the relationships between families/households and natural hazards vulnerability and then employs a principal components analysis to uncover spatial variations in the vulnerability of families and households to hurricane storm surge hazards in Sarasota County, Florida. The analysis identifies and maps five principal components that explain approximately 83% of the variance in family/household population: nuclear families/households; Black families/households; nonfamily, young adult group households; Hispanic families/households; and Asian families/households. Comparison of storm surge risk maps with the locations of these families/households shows the relative vulnerability of each of these family/household categories, with elderly householders living alone on exposed barrier islands being the most vulnerable. The research suggests that family and household structures integrate several socio-demographic vulnerability indicators central to most social vulnerability assessments. Results indicate that future research and hazard mitigation policies should focus on families and households as core analytical units. Findings also suggest that recognizing the diversity of families and households is important to reducing vulnerability to natural hazards.     

Simulation of Storm Surges in the Bay of Bengal Using One-Way Coupling Between NMM-WRF and IITD Storm Surge Model

The storm surge associated with severe tropical cyclones (TCs) in the Bay of Bengal (BoB) is a serious concern along the coastal regions of India, Bangladesh, Myanmar, and Sri Lanka. It is one of the most hazardous elements associated with landfalling TCs other than strong winds and heavy precipitation and about 75% of the casualities in this region are attributed to storm surges. Therefore, it is highly essential to predict the storm surges with greater accuracy at least 2 days in advance for effective evacuation. In the present study, an attempt is made to simulate the storm surges associated with severe TCs in the BoB using one-way coupling of the Non-hydrostatic Mesoscale Model core of Weather Research and Forecasting (NMM-WRF) system with the two-dimensional finite-difference storm surge model developed at the Indian Institute of Technology Delhi (IITD). The NMM-WRF model simulated track, pressure drop, and radius of maximum wind are used to calculate the wind-stress through Jelesnianski wind formulation. The results are compared with the observed/estimated values as provided by the operational/meteorological agencies of India, Bangladesh, and Myanmar. This study suggests that using simulated surface meteorological fields of a high-resolution mesoscale model, the storm surge can be predicted at least 2 days in advance of the actual landfall of TCs with reasonable accuracy. This approach will be helpful in providing disastrous storm warning well in advance in a coastal region, which will help with rapid evacuation from the vulnerable coastal region, relocation as well as protection of valuables, disaster mitigation, and coastal zone management.     

海河流域主要河口闸下通道风暴潮增水研究

建立东海-黄海-渤海大范围风暴潮二维数学模型,对9216台风风暴潮过程进行模拟,分析渤海湾造陆工程前后风暴潮增水对海河流域主要河口(海河口、永定新河口和独流减河口)闸下区域最高潮位的影响,并探讨有效降低河口闸下通道内风暴潮潮位的开发方式。研究表明:渤海湾围填海工程实施后,闸下通道内维持自然地形时,通道内最高潮位高于工程前;闸下通道实施地形开挖后,通道内最高潮位依然高于工程前,但较自然地形条件下抬高幅值有所减小。闸下通道结合开发建设港池航道等工程实施地形开挖,使得通道内水深增加,可降低通道内风暴潮增水幅度。     

Numerical Wave Tank Based on A Conserved Wave-Absorbing Method

Recently the numerical wave tank has become a widely-used tool to study waves as well as wave-structure interactions, and the wave-absorbing method is very important as its effect on the quality of waves generated. The relaxation method and the derived momentum source method are often utilized, however, the damping weight is constant during calculation and repeated trials are required to obtain an acceptable wave-absorbing effect. To address the above- mentioned issues, a conserved wave-absorbing method is developed. The damping weight is determined by solving the mass conservation equation of the absorbing region at every time step. Based on this method, a two-dimensional numerical wave tank is established by using the VB language to simulate various waves by which the validation of this method is evaluated.     

基于有限元法的福建沿岸天文潮风暴潮耦合预报模式研究

采用有限元法建立了一个适用于福建沿岸的天文潮-风暴潮耦合预报模式(FETSCM),模式采用三角网格,在福建沿岸平均网格分辨率为1 km,最高500 m.利用福建沿岸6个潮位站的实测资料对模型进行了验证,天文潮模拟结果与实测吻合良好,5个站位平均绝对误差为22 cm;31场历史台风期间6个站位风暴潮后报模拟误差为24 cm;天文潮-风暴潮耦合总水位的平均极值误差为20 cm,表明该耦合预报模式对福建沿岸的台风灾害预警有较好实用价值.     

含盐风暴潮溃堤洪水数值模拟及风险分析

为了研究三角洲河口风暴潮溃堤时的盐水运动规律,建立一、二维耦合的盐度数学模型对风暴潮溃堤时的盐水运动进行模拟。模型考虑洪泛区建筑物对盐水运动的影响以及溃口的渐变发展过程。用2008年多个测站的实测数据对河网模型的潮位和盐度计算结果进行了验证。将模型应用于珠江三角洲河网某近海溃口风暴潮溃堤的盐水运动模拟,并绘制了最大盐度等值面图。计算结果表明,该溃口大部分区域的溃堤积水盐度超过了4psu,因此,溃堤洪水的高盐度积水影响不容忽视。通过比较“溃堤”和“不溃堤”两种情况下的河网盐度计算结果,发现上游河道的溃堤分流增大了河道的纳潮量,促使涨潮量增大,增大了下游河网的咸潮上溯风险,减弱了上游来流对咸潮的压制效果。     

套管和尾管快速下入工艺在深水钻井中的应用

套管和尾管的下入程序是整个钻井工艺的重要环节。传统的下套管和尾管速度往往较慢且需要周期性地向管柱内灌钻井液。特别是对于深水钻井等钻井液密度窗口较窄的井,掌控套管柱合适的下放速度较困难,极易产生压力“激动”造成井漏。套管和尾管的快速下入工艺是提高作业效率,保证井下安全,满足钻井工艺需要的重要研究方向。本文主要介绍了套管和尾管快速下入工艺技术的主要工作原理、特点、工具组成和操作方法,以及现场应用情况及其注意事项,对作业过程中可能出现的一些问题进行了分析和总结,并提出了相应的建议,对类似的深水井作业具有重要的借鉴意义。     

利用有限区域模式对1979年1月东亚平均环流和寒潮过程的初步模拟试验

利用不同分辨率的有限区域数值模式, 由FGGE III b分析场提供模式的初始条件和随时间变化的侧边界条件,通过长时间连续积分对东亚地区5.625～63.75oN、61.375～138.75oE范围内,1979年1月的平均环流和寒潮过程进行了模拟和试验研究。文中首先考察了在研究时段内长时间积分后,模式的计算性能及其稳定性。结果表明,由于强加于模式的侧边界条件的作用,可以使得误差增长控制在一定范围之内。在此基础上进一步分析了误差的时空分布特征及其成因。通过对24小时变高、24小时变温负中心值和逐日温压场的分     

地震作用下储罐与管道连接波纹管的动力响应

针对储罐与管道连接这个抗震薄弱环节进行研究，考虑了储罐与地基、管道与地基的相互弹性作用及流固耦合作用，使计算模型比较符合工程实际情况。将储罐罐壁看作为刚体，将波纹管部分和管道部分分别用旋转锥壳单元和空间梁单元离散化，通过分析得到波纹管与储罐连接接合面、波纹管与管道连接接合面不同单元之间的位移协调约束方程，并用罚函数法进行处理。根据流体力学速度势理论和有限元法的基本理论，利用哈密尔顿变分原理推导出储罐与管道连接波纹管系统动力分析方程，编制了系统动力分析有限元程序，计算了垂直地震激励不同场地土地基条件下储罐与管道连接波纹管位移响应。     

基于GIS的风暴潮灾害风险区划研究

近年来,风暴潮发生的频率逐年增加,给沿海地区造成巨大的经济财产损失,已成为影响沿海地区社会可持续发展的主要灾害。因此,实现快速的风暴潮风险区划等级评价,对于风暴潮灾害预测预警具有重要意义。本文以青岛地区为例,研究利用GIS分析方法进行风暴潮风险区划的等级评价,实现了风暴潮基础数据读取转换、风暴潮风险区划等级评价和风暴潮灾害预报产品制作一体化处理。