旱耕赤红壤氮、磷流失污染研究

在设置可控条件下的模拟生态系统中研究了旱耕赤红壤的氮、磷流失污染特征,结果显示：旱地土壤随地表流水流失的氮量远大于磷;环境条件一致的情况下,旱地氮、磷污染物输出浓度与作物生育期及施肥时间有关。并指出旱地氮、磷流失可能是珠江广州河段氮、磷含量较高的原因之一     

Effects of Extreme Rainfall on the Export of Nutrients from Agricultural Land

通过流量和水质的同步监测,在径流小区和流域尺度上研究了极端降水事件对氮、磷农田土壤养分流失的影响。研究结果表明:在极端降水事件频发的6￣8月期间,坡地农田随地表径流流失的养分占全年总量的50%以上。水稻田的养分流失占全年的60%左右。而在极端降水量较大的年份,养分流失量也显著高于多年平均值。一年中3次最大降雨事件中输出的氮占全年总量的35.7%￣52.4%,输出的磷占全年总量的46.8%￣66.4%。强降雨过程中小流域出口处的氮、磷浓度随水文过程线的上升而增加,在退水过程虽逐渐下降,但长时间平稳地保持在一个较高的水平。伴随着大流量出现的养分浓度升高导致大量的氮、磷在极短的时间内流失,4次极端降水事件中氮、磷从小流域的输出分别为全年总量的29.2%和44.5%。根据气象预报优化农事活动管理措施,尽量减少在极端降水事件频发期进行翻耕、施肥等农事活动,是减少农田生态系统养分输出和降低农业非点源污染的有效途径。     

地貌灾害间接经济损失评估——以泥石流灾害为例

泥石流是地貌灾害的一种主要类型,泥石流灾害损失目前还无法准确统计,其一是因为对灾害损失的统 计还没有分灾种细化,往往是按大类例如地质灾害甚至是按总类自然灾害来统计;其二是因为灾害损失统计也即 灾情定量评估本身还存在一些科学技术问题尚未解决。灾害损失中的直接经济损失评估只是技术问题,而间接经 济损失评估不仅涉及到技术问题,更重要的是尚有一些科学问题仍未解决。因此,目前还没有一种普遍认同的灾害 间接经济损失评估方法。本文提出了两种方法,调查分析法：理论上可行,操作上困难,实际上只是一种设计方案; 比例系数法：操作上可行,经验成分多,仍然是一种比较粗略的方法。就目前灾害研究水平和防灾减灾实际需要来 考虑,比例系数法仍不失为一种有实用价值的灾害间接经济损失的评估方法。     

基于信息扩散方法的中国台风灾害年月尺度风险评估

利用1985—2014年中国台风灾情和社会经济资料,对中国年和月尺度的台风直接经济损失的时空变化规律进行分析,并采用信息扩散方法开展损失风险评估,为提高台风灾害风险管理能力提供参考。结果表明:全国年及7—9月各月的直接经济损失均呈增加趋势。直接经济损失的月际变化特征明显,8月致灾台风个数多、损失最严重;与1985—1994年相比,后两个10年年内变化幅度大,且9一10月损失大于6—7月。随着直接经济损失水平的增加,发生中、高风险的地区逐渐减少,年直接经济损失≥50亿、≥100亿元水平下,浙江风险概率为全国最高。在10年、20年、30年一遇三个风险水平下,浙江、广东、福建、广西年直接经济损失一直维持特重灾等级;20年、30年一遇风险水平下,北方地区的山东与辽宁年和8月、河北年台风直接经济损失也达特重等级,防台应对不容忽视。     

云南省冬小麦干旱灾损风险区划

应用风险评估技术,对云南省冬小麦干旱灾害风险进行研究,确定了各地冬小麦干旱减产的关键时段,计算了云南省各县冬小麦干旱强度风险、减产风险、抗灾性能、干旱灾损综合风险指数等,并进行了云南省各县冬小麦干旱灾损风险区划。结果表明,云南省由内陆向外部,冬小麦干旱灾损综合风险呈现逐渐加重的趋势     

中国热带气旋潜在影响力指数分析(英文)

Tropical cyclone,a high energy destructive meteorological system with heavy rainfall and gale triggered massive landslides and windstorms,poses a significant threat to coastal areas.In this paper we have developed a Tropical Cyclone Potential Impact Index (TCPI) based on the air mass trajectories,disaster information,intensity,duration,and frequency of tropical cyclones.We analyzed the spatial pattern and interannual variation of the TCPI over the period 1949-2009,and taking the Super Typhoon Saomai as an example have examined the relationship between the TCPI and direct economic losses,total rainfall,and maximum wind speed.The results reveal that China’s TCPI appears to be a weak decreasing trend over the period,which is not significant overall,but significant in some periods.Over the past 20 years,the TCPI decreased in the southern China coastal provinces of Hainan,Guangdong and Guangxi,while it increased in the southeastern coastal provinces of Zhejiang,Fujian and Taiwan.The highest values of TCPI are mainly observed in Taiwan,Hainan,the coastal areas of Guangdong and Fujian and Zhejiang’s southern coast.The TCPI has a good correlation (P=0.01) with direct economic loss,rainfall,and maximum wind speed.     

Risk-based damage potential and loss estimation of earthquake scenarios in the moderate endangered Austrian Federal Province of Tyrol

Although geophysical hazards like earthquakes can lead to tremendous losses, they are often neglected or not considered in risk analyses within an Alpine context. However, lately and especially in the framework of multi-risk analyses, earthquake risk studies are being increasingly implemented within an Alpine relation too. The presented study was conducted to quantitatively estimate potential consequences of earthquake events in the Austrian Province of Tyrol. The methodological study framework integrates the general risk components (i) hazard, (ii) elements at risk, and (iii) vulnerability. They are considered on a regional scale, accepting pragmatic approaches with simplified procedures and assumptions. Scenarios for different potential epicentres were calculated based on two different macroseismic hazard maps derived from punctual ground motion values of the building code and microzonation studies. The maps take into account the design event definitions of existing building code and a, thereupon based, simple and mono-causal Maximum Credible Earthquake assumption. Corresponding elements at risk and damage potentials were identified and potential losses were estimated under consideration of different vulnerability approaches. It can be shown that most scenarios based on the design event definition of the Austrian and European building codes, respectively have the potential of building and inventory losses solely of some hundred million up to approximately €4 billion. Additional, building and inventory losses of maximum credible events can lead to losses of more than €7 billion merely in connection with the primary earthquake event neglecting all other cascading effects.     

Comparison of interception losses in a broadleaved native forest and a Pseudotsuga menziesii (Douglas fir) plantation in the Andes Mountains of southern Chile

For a 26 month period, between 1 February 1998 and 31 March 2000, total precipitation, throughfall, stemflow and interception losses were measured for two different forest covers, one a managed broadleaved native forest and the other a Pseudotsuga menziesii (Mirb.) Franco (Douglas fir) plantation. Regressions between throughfall and stemflow and total precipitation (P) for individual storms and forest covers were computed and also for values of interception losses (expressed as a percentage of P) and P for each forest cover and period of development of the forest vegetation. Results obtained demonstrate the importance of forest canopies in rainfall distribution processes and for the availability of water resources. Also, that these forests generate particular interception patterns not strongly associated with the variation in crown cover throughout the year. These patterns are more closely related to the characteristics of rainfall and meteorological conditions during the growing and dormant periods. Copyright © 2002 John Wiley & Sons, Ltd.     

Assessment of a method used to time adjust past storm losses

A widely used method for adjusting past annual storm losses to present day values, needed to address the ever-changing socio-economic conditions, was assessed. The property insurance industry developed a comprehensive method for adjusting losses in past years to current year loss values. Characteristics of hurricanes occurring 50+ years ago and those in the recent years were examined to find similar early and recent pairs of storms for a comparative evaluation of their property losses. One pair found was Hurricanes Hazel (1954) and Hugo (1989), and another pair with similar features was Hurricanes Carol (1954) and Bob (1991). The insurance-based adjusted property loss values for these two pairs of storms were compared to determine if the early year values were comparable to the recent year values. The adjusted losses of the two pairs of hurricanes were found to have small differences of 7.8% and 8.1%, and these differences were due to somewhat different storm paths and slightly higher wind speeds in the two storms having higher losses. The adjustment method appears to adequately capture time differences in storm losses due to changes in population, wealth, inflation, structural density, and insurance coverage.     

Decision support for conceptual performance‐based design

Performance assessment implies that the structural, non‐structural, and content systems are given and that decision variables, DVs, (e.g. expected annual loss, mean annual frequency of collapse) are computed and compared to specified performance targets. Performance‐based design (PBD) is different by virtue of the fact that the building and its components and systems first have to be created. Good designs are based on concepts that incorporate performance targets up front in the conceptual design process, so that subsequent performance assessment becomes more of a verification process of an efficient design rather than a design improvement process that may require radical changes of the initial design concept. In short, the design approach could consist of (a) specifying performance targets (e.g. tolerable probability of collapse, acceptable dollar losses) and associated seismic hazards, and (b) deriving engineering parameters for system selection, or perhaps better, using the relatively simple design decision support tools discussed in this paper. Copyright © 2005 John Wiley & Sons, Ltd.