共查询到20条相似文献，搜索用时 31 毫秒
1.
Pramod Kumar Sharma 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2018,12(3):218-233
Flood hazard evaluation is an important input for Nuclear Power Plants external events safety studies. In the present study, flood hazard at various nuclear sites in India due to rainfall has been evaluated. Hazard estimation is a statistical procedure by which rainfall intensity versus occurrence frequency is estimated from historical records of rainfall data and extrapolated with asymptotic extreme value distribution. Rainfall data needed for flood hazard assessment are daily annual maximum rainfall (24?h data). The observed data points have been fitted using Gumbel, power law and exponential distribution, and return period has been estimated. To study the stationarity of rainfall data, a moving window estimate of the parameters has been performed. The rainfall pattern is stationary in both coastal and inland regions over the period of observation. The coastal regions show intense rainfall and higher variability than inland regions. Based on the plant layout, catchment area and drainage capacity, the prototype fast breeder reactor (PFBR) site is unlikely to be flooded. 相似文献
2.
Erik Rüttener Juan José Egozcue Dieter Mayer-Rosa Stephan Mueller 《Natural Hazards》1996,14(2-3):165-178
Seismic hazard analysis is based on data and models, which both are imprecise and uncertain. Especially the interpretation of historical information into earthquake parameters, e.g. earthquake size and location, yields ambiguous and imprecise data. Models based on probability distributions have been developed in order to quantify and represent these uncertainties. Nevertheless, the majority of the procedures applied in seismic hazard assessment do not take into account these uncertainties, nor do they show the variance of the results. Therefore, a procedure based on Bayesian statistics was developed to estimate return periods for different ground motion intensities (MSK scale).Bayesian techniques provide a mathematical model to estimate the distribution of random variables in presence of uncertainties. The developed method estimates the probability distribution of the number of occurrences in a Poisson process described by the parameter . The input data are the historical occurrences of intensities for a particular site, represented by a discrete probability distribution for each earthquake. The calculation of these historical occurrences requires a careful preparation of all input parameters, i.e. a modelling of their uncertainties. The obtained results show that the variance of the recurrence rate is smaller in regions with higher seismic activity than in less active regions. It can also be demonstrated that long return periods cannot be estimated with confidence, because the time period of observation is too short. This indicates that the long return periods obtained by seismic source methods only reflects the delineated seismic sources and the chosen earthquake size distribution law. 相似文献
3.
M. Bini G. Zanchetta E. Regattieri I. Isola R. N. Drysdale F. Fabiani S. Genovesi J. C. Hellstrom 《第四纪科学杂志》2020,35(6):791-802
Study of the climate in the Mediterranean basin during different historical periods has taken on a particular importance, particularly regarding its role (together with other factors) in the evolution of human settlement patterns. Although the Roman age is traditionally considered a period with a favourable climate, recent studies have revealed considerable complexity in terms of regional climate variations. In this paper, we compare the hydrological change from speleothem proxy records with flood reconstructions from archaeological sites for Northern Tuscany (central Italy). We identify a period of oscillating climatic conditions culminating in a multidecadal dry event during the 1st century bc , followed by a century of increased precipitation at the beginning of the Roman Empire and subsequently a return to drier conditions in the 2nd century ad. The period of rainfall increase documented by the speleothems agrees with both the archaeological flood record as well as historical flood data available for the Tiber River, ca. 300 km to the south. These data also suggest a return to wetter conditions following the 3nd and 4rd centuries ad. 相似文献
4.
历史时期土地利用变化研究方法综述 总被引：3，自引：0，他引：3
历史时期土地利用/覆盖变化一直是国际关注的热点问题之一。研究历史时期土地利用/覆盖变化,不但可以认识和理解陆地表层景观环境在过去的变化过程,而且对当前的土地利用方式或预测未来土地利用/覆盖变化和发展都有重要的指导意义。依据使用的主要数据源、处理方法和研究思路,从历史文档资料、古地图、考察/调查报告、模型模拟与综合多源信息和多学科知识的方法等5个方面综述国内外历史时期土地利用变化研究方法的现状。根据不同数据源的特性,探讨分析利用不同方法开展历史时期土地利用变化研究的优缺点及其不确定性:①历史文档资料种类繁多,包含的信息量巨大,但存在很多噪音和遗漏,且缺乏直观的空间信息;②古地图可以提供比较直观的空间位置信息,但是历史时期的绘图技术落后,且土地利用类别划分较粗;③过去的野外考察/调查资料记录比较规范,但时空尺度较小,难以满足较早时期的研究需要;④利用模型进行模拟研究可选择的时空尺度范围较大,但模型的选择和建立比较复杂,对驱动数据和初始值要求较高。最后,提出只有综合多源信息和多学科的知识才能比较完整地理解历史时期土地利用变化过程,融合多源信息和多学科知识的方法将是今后进行历史时期土地利用变化研究的主要思路。 相似文献
5.
In evaluating potential impacts of climate change on water resources, water managers seek to understand how future conditions may differ from the recent past. Studies of climate impacts on groundwater recharge often compare simulated recharge from future and historical time periods on an average monthly or overall average annual basis, or compare average recharge from future decades to that from a single recent decade. Baseline historical recharge estimates, which are compared with future conditions, are often from simulations using observed historical climate data. Comparison of average monthly results, average annual results, or even averaging over selected historical decades, may mask the true variability in historical results and lead to misinterpretation of future conditions. Comparison of future recharge results simulated using general circulation model (GCM) climate data to recharge results simulated using actual historical climate data may also result in an incomplete understanding of the likelihood of future changes. In this study, groundwater recharge is estimated in the upper Colorado River basin, USA, using a distributed-parameter soil-water balance groundwater recharge model for the period 1951–2010. Recharge simulations are performed using precipitation, maximum temperature, and minimum temperature data from observed climate data and from 97 CMIP5 (Coupled Model Intercomparison Project, phase 5) projections. Results indicate that average monthly and average annual simulated recharge are similar using observed and GCM climate data. However, 10-year moving-average recharge results show substantial differences between observed and simulated climate data, particularly during period 1970–2000, with much greater variability seen for results using observed climate data. 相似文献
6.
钻进工程数据库(DEDBASE)是在微型机上用DBASE软件和BASIC软件联合开发的计算机系统,它是微型机在钻进工程中先进的和重要的应用之一,是实现钻进工程生产管理、技术管理、技术咨询及优化决策科学化和现代化的基础。 钻进工程数据库(DEDBASE)包括钻进工程数据文件集合(DEDFA),数据库服务系统(DSS)以及动态优化分析系统(DOAS)。其中动态优化分析系统(DOAS)是钻进工程数据库的分析机构和应用程序,它以贮存在钻进工程数据文件集合中的各类钻进数据为基础,并结合当前的钻进条件(如钻进钻头、钻进规程和平均钻速等)能够用于:(1)查询钻进史料;(2)分析钻进规律;(3)单只钻头优化;(4)优化决策及监视岩性变化。通过分析室内模拟钻进数据韧野外钻进数据,证明钻进工程数据昨(DEDDASE)的上述应用具有良好的有效性及可信性。 相似文献
7.
《Geoforum》2002,33(2):255-269
Inter-state water disputes occur in federal political systems. They stand at the intersection of two branches of law: federalism under constitutional law, and water law – specifically river basin regulation. In India, constitutional federalism is the outcome of colonial history. River-basin regulation is the outcome of developments in capitalism within the social context of Europe and United States, later universalised as international law under the Helsinki Rules and the International Law Commission Convention on Law of the Non-Navigational Uses of International Watercourses. When national law evolved in the historical context of colonisation, intersecting with international law evolved in the historical context of European capitalism, it reproduced imperial-colonial relations of super-ordination and sub-ordination in relation to water. It created an internal schism that locks the water sector into a developmental catharsis. 相似文献
8.
水质数据计算机管理系统分析 总被引：2，自引：0，他引：2
水质数据计算机管理系统是用计算机来处理水质数据，完成从原始的计算、分析、统计、斩汇编、水质评价一直到数据存贮入库，绘制污染状况图等一系列工作，既提高了水质数据的可信度，又缩短了水质数据采集，服务的周期。系统通过对大量用记需求信息的归纳，提出了符合水质数据规律的概念模型，采用分层技术进行系统分析，使整个系统功能齐合，用户界面友好，操作方式灵活，输出内容丰富，并可在ＶＡＸ系列计算机入ＩＢＭ系列微机上运 相似文献
9.
钱塘江河口是世界著名强潮河口。基于历史文献资料,系统梳理考证了明代(公元1368—1644年)钱塘江河口潮灾记录,分析了潮灾的空间、时间分布特征:(1)北岸潮灾远多于南岸,海门以上河口段与海门以下河口段潮灾次数基本持平,但均少于河口湾段。(2)潮灾在南北两岸的空间分布上,存在转移与变迁,由此导致两岸分别存在明显的平缓期—爆发期—平缓期交替,但平缓期与爆发期的时长并不固定。(3)潮灾强度变化与潮灾频次分布有较强关联,高强度潮灾多发于潮灾频发期。结合历史气候、江道地形等自然环境背景,探讨了影响潮灾时空分布的要素,认为钱塘江潮灾发生的频次及规模大小与流域内干湿变化及历史气温升降有明显关联,而历史极端潮灾则常是多种要素耦合的结果。 相似文献
10.
超长系列的降水资料是分析气候变化和预估未来区域水安全形势的重要支撑,但目前观测资料只有几十年时间尺度,利用相关历史文献资料进行系列重建是延长现有观测资料的主要手段。基于《中国近五百年旱涝分布图集》和1959年以来实测降水资料,重建1470—2019年中国东部季风区的长序列降水数据,分析近550 a以来区域降水变化规律,剖析气候自然变异规律和人为气候变化对历史降水的影响,并通过CMIP6中等分辨率气候系统模式下的4种情景降水数据预估未来降水变化趋势。研究表明:①东部季风区降水年际分布不均,有明显的丰枯变化,1470—1691年整体处于枯水期,1692—1924年处于丰水期,1925年至今处于枯水期,存在准181 a周期;② 1991年后人为气候变化的影响已经显现,海河、黄河下游和长江流域部分降水倾向率发生显著变化,东部季风区总体降水增加趋势加快;③在未来气候变化情景下多年平均降水量较基准期（1961—1990年）显著增加,季节性变化加大,区域旱涝风险加剧。由于未来气候情景的不确定性,未来降水趋势预测的可信度尚未可知,需要进一步增强风险分析。 相似文献
11.
《Geoforum》2016
This article examines how law is implicated in the formation of place, and how place in turn can shape law. It is an empirical explication of Latour’s call for researchers to study the global through its local instantiations. Drawing upon recent theoretical work in both material culture studies and legal geography the article examines the interplay of law and material formations at one originating site, Sir Richard Arkwright’s Cromford Mills in Derbyshire in order to examine the creation and circulation of a new form of place in the late eighteenth century: the industrial scale cotton mill. It shows how a diverse range of legal elements ranging across patent law, the Calico Acts and ancient local Derbyshire lead mining laws all helped to shape that place-form, its proliferation across the United Kingdom, and ultimately further afield. In doing so the article conceptualises processes of localisation, translocalisation and thing-law by which the abstractions of both place-forms and law elements become activated through their pragmatic local emplacement. Whilst the case study concerns 200 year old place-making machinations, many of the spatio-legal articulations of Arkwright and his opponents have a surprisingly modern feel about them. The paper therefore advocates the benefits of a longitudinal, historical approach to the study of place-making, and in particular, calls for a greater attentiveness in legal geography to law’s role in the intentional formation of (work)places by their owners. 相似文献
12.
Elena Fernández Ana Colubi Gil González-Rodríguez Soledad Anadón 《Natural Hazards》2012,62(2):459-483
The importance of the historical information in flood analysis has previously been underlined. In this context, we present an integral methodology aimed at the establishment of return periods of different flood units on the unique basis of historical data. Specifically, the reconstruction of the flood chronology extended back to 1900, complemented with a new (historical data-based) event intensity index, and the return period estimation will be addressed. Since some of the historical data are collected from interviews and other sources with different degrees of precision and reliability, two kinds of uncertainty will be considered; namely the statistical variability and the imprecision. We propose an innovative methodology involving intervals (ranges), fuzzy sets, and weights to formalize and average the criteria that determine the importance of the different events. On the other hand, to take into account the statistical variability, we propose to estimate the return period in a flexible and efficient way by considering bootstrap confidence intervals. The methodology is particularly useful at ungauged, or partially gauged, flood inundation areas, where the existing flow gauge stations do not give the flood series at the point of interest. A case study developed in Spain is discussed. The results are supported by two recent events, which have been mapped at 1:5000 scale. 相似文献
13.
The return period is a key element used for snow-avalanche characterization. To calculate the return period, historical data regarding past snow-avalanche activity are required. In mountain areas where past snow avalanches are poorly documented, dendrogeomorphic approaches constitute a reliable method for the reconstruction of past snow avalanches at the temporal scale of living trees. This paper presents an automated method for calculating the snow-avalanche return period using a digital elevation model and the location of the trees disturbed by every reconstructed snow-avalanche occurrence. Unlike the existing method, the method we propose requires neither the calculation of return period for every sampled tree nor the use of interpolation. This new method is based on the determination of spatial extent for every past snow-avalanche occurrence using the upslope area algorithm. The number of past snow-avalanche occurrences is calculated for every pixel of the path. The chronology length is divided by the number of past snow-avalanche occurrences to obtain the return period. In the present paper, both the proposed method and the existing method are applied to calculate the return period for three confined snow-avalanche paths located in Parâng Mountains, part of the Romanian Carpathians. Results are compared and discussed. 相似文献
14.
Cumulative Benioff strain-release, modified Omori's law and transient behaviour of rocks 总被引：1，自引：1，他引：1
Irreversible thermodynamic theories with internal state variables can be used to derive a general constitutive law for both transient and steady-state behaviours of rocks. This constitutive law can represent the concepts of damage and damage evolution in either the fibre-bundle model or continuum damage mechanics. We have previously proposed an empirically based constitutive law for both the transient and steady-state behaviours of rocks ultimately derived from laboratory experimental data. We show here that this law is concordant with the general constitutive law derived from irreversible thermodynamic theories, and that the relaxation modulus has a temporal power–law that depends on a structural fractal property of rocks. Our constitutive law predicts forms for the cumulative Benioff strain-release for precursory seismic activations and the modified Omori's laws of aftershocks, both aspects of the temporal fractal properties of seismicity. These seismic properties can also be derived by the fibre-bundle model or continuum damage mechanics. Our model suggests that these time-scale invariant processes of seismicity may be regulated by the fractal structures of crustal rocks. 相似文献
15.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》1999,24(2):139-144
In recent years a great effort has been made to quantitatively model major historical events in Europe, searching for models that are compatible with both seismic, hydrodynamic and sedimentological evidences. The possibility to do so, with the available modelling techniques, has been checked against instrumental tsunami and seismological data. Most of this effort has been made within the projects GITEC and GITEC TWO.The quantitavive data that can be gathered from historical sources are: extension of the source area, wave heights, first wave polarity and, only rarely, travel times and time intervals between main waves. With this data the accuracy of source studies is a function of both the model uncertainty (can tsunami waves be accurately modelled ? are seismic parameters compatible with tsunami source parameters ?) and the observation errors. These are large when we deal with historical documents hundreds of years old.Here we present the conclusions obtained from the study on the 1755 Lisbon earthquake and tsunami. The available historical data are reliable enough to allow a good source determination and, surprisingly, the results obtained differ from those obtained from previous macroseismic studies.The analysis of the results obtained in the tsunami modelling, checked against the macroseismic data, allow the identification of an important seismo and tsunamigenic area, close to the SW Portuguese coast, that must also be taken into consideration for the evaluation of seismic hazard. 相似文献
16.
《Comptes Rendus Geoscience》2008,340(9-10):644-650
The knowledge of past catastrophic events can improve flood risk mitigation policy, with a better awareness against risk. As such historical information is usually available in Europe for the past five centuries, historians are able to understand how past society dealt with flood risk, and hydrologists can include information on past floods into an adapted probabilistic framework. In France, Flood Risk Mitigation Maps are based either on the largest historical known flood event or on the 100-year flood event if it is greater. Two actions can be suggested in terms of promoting the use of historical information for flood risk management: (1) the development of a regional flood data base, with both historical and current data, in order to get a good feedback on recent events and to improve the flood risk education and awareness; (2) the commitment to keep a persistent/perennial management of a reference network of hydrometeorological observations for climate change studies. 相似文献
17.
18.
基于台湾66个站点年最大日雨量历史资料、台湾中央气象局2009年8月8~10日莫拉克台风暴雨期间251个台湾雨量站逐时降雨资料和香港地区65个雨量站的历史逐时降雨资料,以及与香港相邻的3个广东省雨量站(西沥站、横岗站和深圳站)资料,利用分时段地形增强因子法(SDOIF),将莫拉克台风暴雨最大24h实测暴雨中的辐合雨分量分割,并将其辐合雨成分移置到香港地区,与香港地区24h平均地形增强因子相结合,估算出香港地区的可能最大降水。结果显示,莫拉克最大24h降雨量中地形的增强幅度约为45%;得出香港地区最大24h平均可能最大降水分布图,其最大中心值1230.2mm(未考虑水汽放大),与香港地区历史暴雨中心一致,均发生在大帽山附近。 相似文献
19.
The knowledge of past events is important for the assessment of debris-flow hazard. Amongst the sources of information, documents
from historical archives are particularly important in sites where the debris flows cause damage to urban areas and transportation
routes. The paper analyses the availability of historical documents on debris flows in Northeastern Italy and discusses factors
that can influence the building of time series from archive data both at regional and single basin scales. An increased number
of debris flows was observed in the studied region for the last decades. This could be due both to an increased frequency
of the events and to a larger availability of information: the analysis carried out indicates that the latter factor is probably
the most influencing. The importance of factors, which affect the collection of data, including the conservation of documents
and the presence and fragility of the elements at risk, is stressed in view of a wise use of historical data on debris flows. 相似文献
20.
本文尝试由历史文献记载直接反演网格式降水量距平场.这项探讨是利用计算机的文字处理功能,以"中国三千年气象记录总集"1)为基本资料,通过对各地点、各年份气候记载的赋值处理,用Cressman插值方法初步反演生成1501～1900年网格降水量距平场,其时间分辨率为1a,空间分辨率为1°×1°经纬度.这样的网格资料定量含义明确,空间和时间的连续性好,可以方便地与数值模拟结果进行对比,和进行降水的时间、空间变率研究,还可由它生成空间间隔均匀的降水量距平指数的时间序列,进行气候变化分析. 相似文献