桂林“5.9”山体滑坡的暴雨成因分析

对造成2011年5月9日广西桂林咸水乡山体滑坡的暴雨成因进行了分析,结果表明,滑坡是由于暴雨因素诱发的地质灾害,短时强暴雨是造成山体滑坡的直接原因.大量的水汽传送到滑坡点,同时低层辐合抬升,因而滑坡点是大暴雨的发生地.滑坡发生滞后强降雨结束2.5h.滑坡点位于暴雨中心带,暴雨区位于高空急流的右侧,200h Pa为强烈辐散区,高空辐散带的走向与山脉走向一致.西南低空急流与地形的相互作用是暴雨形成的直接原因,雷达回波显示在“湘桂走廊”存在强风速的出流与横向风速梯度,对应反射率有弓状回波,同时具有前侧V形人流缺口和后侧V形下沉缺口等对流单体特征.     

陕西2012年极端天气气候事件与气象灾害

利用极端天气气候事件监测系统监测结果,分析了陕西1981-2012年极端天气气候事件出现次数和强度,发现2012年陕西极端天气气候事件次数少于多年平均值,但华阴7月2-4日、佳县7月24-28日极端降水事件强度之大,为历史罕见,佳县27日降水量、26-28日3d降水量均超过百年一遇的水平,造成严重人员伤亡和经济损失.说明即便是在极端天气气候事件出现次数少,气候年景较好的年份,局地也会出现历史罕见的极端事件和灾害.此外,还分析了极端天气气候事件次数与灾情年景评估指数之间的相关性.     

2012年我国主要气象灾害回顾

2012年,我国主要气象灾害为暴雨洪涝、热带气旋、干旱、高温、连阴雨、雪灾、风雹及沙尘暴.其中暴雨过程多,长江、黄河、海河等流域先后出现明显汛情,北京、甘肃、四川、重庆、云南、贵州、宁夏、青海和新疆等地出现山洪地质灾害,但暴雨洪涝灾情偏轻;热带气旋数量接近常年,但影响时间集中、范围广,灾情偏重;阶段性干旱明显,但干旱范围小,影响偏轻;中东部地区高温日数多,极端性强,南方部分地区早稻遭受轻至中度高温热害;区域性、阶段性低温阴雨天气多发,对农业生产造成一定影响;降雪量明显偏少,雪灾偏轻;风雹日数少,灾害损失偏轻;春季北方沙尘日数为近52年最少;中东部地区雾霾天气频繁,对交通运输产生较大影响.总体而言,2012年为我国气象灾害偏轻年份.     

‘Schismo‐urbanism’: cities,natural disaster,and urban sociology

This paper examines a city and a natural disaster, specifically New Orleans, Louisiana, after Hurricane Katrina of August 2005. Recovery here is ongoing and the process of return is incomplete, with long‐term dislocation to other cities in the United States, such as Houston, Texas. The question arises as to how planning and stratification influence evacuation and return/dislocation and how they result in a particular practice of adaptation. This interrelated process is conceptually integrated and termed ‘schismo‐urbanism’ and is analysed within a multidimensional theoretical framework to evaluate aspects of urban sociology and natural disasters. Empirical research is based on a quantitative and qualitative mixed‐method case study. Data were collected during two rounds of field research in New Orleans and Houston in 2007 and 2009. As a comparative socio‐spatial study of affected and receptor communities, it makes a novel theoretical and methodological contribution to research on urban disasters in the context of continuing and rapid social change, and is targeted at disaster researchers, planning theorists and practitioners, and urbanists.     

Measuring vulnerability to natural hazards: a macro framework

The measurement of vulnerability—defined here as the asymmetric response of disaster occurrences to hazardous events—signifies a key step towards effective disaster risk reduction and the promotion of a culture of disaster resilience. One of the reasons for not being able to do the same in a wider context is related to conceptual, definitional, and operational issues. This paper presents an operationally feasible framework for conducting this task and measures revealed macro vulnerability as a function of disaster risk and hazard probability. The probabilities of hazard and its perceived disaster risk were obtained from past data and from probability distributions. In this paper, the corresponding analytical framework is constructed using the case study of floods in Assam, India. The proposed indicator will help policymakers to draw on available macro‐level data to identify the regions that are vulnerable to disasters, where micro‐level disaster vulnerability assessments could be performed in greater detail.     

Return or relocate? An inductive analysis of decision‐making in a disaster

This paper proposes an inductive analysis of the decision as to whether to return or to relocate by persons in the State of Louisiana, United States, who evacuated after Hurricanes Katrina and Rita in August and September 2005, respectively. Drawing on interviews with evacuees in these events and extensive fieldwork in the impacted area, the paper seeks to identify the folk dimensions of the decision‐making process, assess their arrangements, and situate the process in the larger context of risk and resilience in an advanced society. It suggests that, despite the material and emotional upheaval experienced by affected persons, the decision‐making process is a rational endeavour combining a definite set of tightly interconnected factors, involving material dimensions and substantive values that can act in concert or in conflict. In addition, it indicates that there are significant variations by geographic areas, homeownership, and kind of decision. Some theoretical implications, practical measures, and suggestions for future research are examined.     

Disaster devastation of US communities: long-term demographic consequences

This paper describes demographic changes resulting from devastating natural disasters in which at least half of the community's structures suffered major damage or total destruction. Considering 92 US communities that suffered disasters (mainly from hurricanes, river flooding, and tornadoes) between 1992 and 2008, locations that were already experiencing declining populations before their disaster were most likely to experience large post-disaster population losses. Communities suffering severe flooding were most likely to lose over a third of their population. Population movement typically occurred regardless of whether the community formally relocated. Small communities were particularly at risk of losing population following destruction, particularly when they lacked schools. Communities with higher home vacancy rates before their devastation were significantly more likely to experience large population declines. Wealthier communities and those located nearer metropolitan cities were most likely to retain their populations following major destruction, yet overall pre-disaster home values and median incomes in the communities were well below national averages. Race and Hispanic population were not significantly related to post-disaster population change in the overall study.     

The humanitarian response costs of climate change

This research attempts to improve understanding of how climate change may affect international humanitarian spending, using existing international databases that track disaster occurrence and humanitarian costs. A range of potential impact scenarios is developed employing four distinct methodological approaches. The findings indicate that climate change will have a significant impact on humanitarian costs and the increase could range from a 32 per cent increase (taking into account only changes in frequency of disasters) to upwards of a 1,600 per cent increase when other criteria, such as intensity, are also taken into account. The paper further highlights that extreme weather events do not occur in isolation and the increasing interconnectedness of world economic and political systems has made disasters more complex and destructive. It makes a number of recommendations, including the need for more rigorous and systematic collection of disaster-related data and more constructive interaction between the humanitarian and climate change communities on future research, planning and action.     

2013年北川聚落空间的地质灾害灾情分析

北川羌族自治县是2008年汶川8.0级地震的极重灾区之一。2013年7月8-12日,北川县境内普降暴雨,引起地质灾害事件大面积爆发。洪灾之后的灾情普查数据表明,县域内共有1 318个居民点受到各类地质灾害的威胁,这些地质灾害点的类型多样、分布广泛并且所造成的危害严重。根据灾情普查数据,按乡镇单元提取了各自的灾害点数量、受威胁面积、受威胁户数、受威胁人数、受威胁财产以及防治费用等6个指标,采用主成分分析方法来进行地质灾害灾情的综合评价,根据各乡镇的综合得分对乡镇的灾情进行了排序。这个评价结果较好地反映了各乡镇之间的灾情差异,也为上一级政府进行诸如制定乡镇社会经济发展指标、决定防灾减灾资金及技术力量的投向等行政决策提供了直接依据。