共查询到19条相似文献，搜索用时 130 毫秒
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从干旱定义与识别、点干旱频率分析和区域干旱频率分析3个方面系统阐述了干旱频率分析研究进展和存在问题,归纳了适用于干旱频率分析的干旱定义,干旱识别存在的主要问题以及区域干旱频率分析研究的3种途径。提出综合利用研究区域水文气象特性、干旱成因、旱情、旱灾,并结合前期的大气环流条件等信息来描述和识别干旱,重点开展对干旱特征变量的理论分布、干旱事件重现期公式和经验频率公式等基本理论的研究,关注区域干旱频率分析,注重对径流、土壤水、地下水和供水系统的干旱特性分析。 相似文献
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干旱指标的理论分析与研究展望 总被引：81，自引：3，他引：78
干旱作为最严重的气象灾害之一,已经对我国社会经济和人民生活造成严重影响。尽管关于干旱和干旱指标已有大量研究,但是由于干旱自身的复杂特性和对社会影响的广泛性,干旱指标都是建立在特定的地域和时间范围内,难以准确反映干旱发生的内在机理。为此有必要对干旱定义及国内外主要的干旱指标加以综述和评价,为干旱的监测和评估,特别是为全球变化中的气候-植被关系研究提供方法和依据。将干旱分为 4种类型：气象干旱、农业干旱、水文干旱和社会经济干旱,并对当前国内外主要的干旱指标进行介绍,指出了其适用范围,并在归纳现有干旱指标不足的基础上提出了干旱指标的研究方向和任务。 相似文献
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干旱通过相互关联的陆气系统与水文循环过程进行传播,在不同的地理时空传播演变成不同的干旱类型,如水文干旱、农业干旱、生态干旱和社会经济干旱等。在全球气候变暖和人类活动加剧的背景下,不同类型干旱之间的传播演变过程呈现出更多的不确定性。近10年来,对干旱传播时空特征、研究方法、演变过程以及驱动因素的理解逐步加深,但明确的科学观点仍相对匮乏。因此,从干旱传播的定义出发,系统分析了该问题的科学内涵,阐明了干旱传播研究的发展阶段。随后综合归纳了当前干旱传播的6类定量研究方法,包括阈值方法与游程理论、相关分析、因果分析、交叉小波、概率模型以及气象水文模型。并进一步从气象—水文和气象—农业两类干旱传播情景以及干旱传播驱动力方面,分析总结了当前形成的主要科学认识,揭示了全球范围内干旱传播研究发现的传播顺序、阶段阈值、时空异质性和人类驱动过程。最后分析指出了未来干旱传播研究面临的一系列挑战,包括进一步挖掘传播过程时空异质性、突破数学与物理知识鸿沟建立可信模型以及融入跨领域知识实现全过程的传播解析。对国内外干旱传播研究的前沿进展和挑战进行了系统分析,可为下一步干旱灾害分析与科学管理提供关键理论与方法支撑。 相似文献
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区域气象干旱评估分析模式 总被引：1，自引：0，他引：1
为应对全球范围内日益严重的干旱问题,对区域气象干旱相对完整的评估分析模式开展了探讨。提出了从区域气象干旱识别到干旱特征值计算,再到干旱特征多变量分析的3个分析评估步骤。并以渭河流域为例,对研究区域进行了矩形干旱评估单元划分,选取了RDI（Reconnaissance Drought Index）为评估指标对区域内各单元各时段的干旱状态进行了识别,结果与历史记载的干旱年份吻合较好。分别采用了分布拟合、相关系数和Copula函数等统计学方法对区域干旱的干旱特征值（干旱历时、干旱面积、干旱强度和干旱频率）进行了特征分析,得出了一系列的单变量、双变量及多变量特征分析对比结果。通过对各类分布函数的计算和绘图,得到了渭河流域干旱事件发生的条件概率和重现期,形成了一套相对完整的区域干旱评估分析模式。 相似文献
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干旱灌区盐碱地形成及改良利用区划综述 总被引：3，自引：0，他引：3
一直以来,干旱灌区盐碱地形成机理研究、盐碱地改良利用研究是干旱灌区盐碱地研究的主要内容。本文比较系统地阐述了盐碱地形成的影响因素、近年来国内干旱灌区水盐运动机理研究概况,并对盐碱地改良利用方法作了比较全面的总结,对盐碱地的合理开发利用和改良实践中所用的一些区划方法做了综合阐述。 相似文献
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对区域干旱的概念和计算方法进行了研究,认为干旱问题应根据不同的干旱特征分区进行研究并提出针对性的解决措施。干旱研究不仅要考虑到干旱的水文特征,而且要考虑干旱风险所带来的后果。提出了分析干旱问题的理论框架。并将黄河下游引黄灌区划分为6个子区,应用多变量随机模型生成了月降水量资料系列。利用了33年的月降水量资料率定模型参数。应用生成的月降水量系列从理论风险性的观点研究了区域干旱问题。 相似文献
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干旱持续时间久、影响范围大,时空连续性是干旱的基本特征,以往研究大多考虑单变量或双变量。通过给定阈值识别干旱斑块和判断两相邻时间干旱的连续性,提出了时空连续的干旱事件三维识别方法,用干旱历时、干旱面积、干旱烈度、干旱强度和干旱中心位置5个特征变量对一场干旱事件进行度量;提出了基于Copula函数的干旱历时-面积-烈度三变量频率分析方法。以中国西南地区为例,采用SPI(Standard Precipitation Index)干旱指标识别了近52年发生历时等于或大于3个月的干旱事件,一共78场,其中2009年8月至2010年6月最严重干旱事件的重现期为94年一遇。通过比较概率分布函数和Copula函数,表明在干旱频率分析时需要考虑干旱历时、面积、烈度3个特征变量。 相似文献
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水库径流调节对水文干旱的影响分析 总被引：3，自引：0，他引：3
对水文干旱研究做了简要综述,在此基础上,分别探讨了不考虑径流调节和考虑径流调节情况下的水文干旱分析方法.利用人工生成径流系列,以实际需水量作为截断水平产生干旱事件,得到了天然水文干旱的统计特征,主要包括不同频率(重现期)的水文干旱烈度、历时和强度;考虑水库系统对径流的调节作用,在水库采用SOP运行规则下,分析了径流调节下的供水系统水文干旱和判断依据,得出了考虑径流调节下的水文干旱统计特征.对两种情况下水文干旱统计特征进行对比分析,定量刻画了水库径流调节对水文干旱的影响. 相似文献
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农业干旱风险评价技术应用初探 总被引：2，自引：0，他引：2
本文应用风险分析技术对农业干旱风险评价方法作了初步探讨,建立以风险理论为核心的农业干旱风险评价模型。并以湖南邵阳市为研究区,进行农业干旱风险评价研究,得到该地区旱作物干旱灾害风险分布情况,为该地区干旱风险管理提供决策依据。 相似文献
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Groundwater drought is a specific type of hydrological drought that concerns groundwater bodies. It may have a significant adverse effect on the socio-economic, agricultural, and environmental conditions. Investigating the effect of different climatic and anthropogenic factors on groundwater drought provides essential information for sustainable planning and management of (ground) water resources. The aim of this study is to identify the influencing factors on groundwater drought in north-western Bangladesh, to understand the forcing mechanisms. A multi-step methodology is proposed to achieve this objective. The standardised precipitation index (SPI) and reconnaissance drought index (RDI) have been used to quantify the aggregated deficit between precipitation and the evaporative demand of the atmosphere, i.e. meteorological drought. The influence of land-cover patterns on the groundwater drought has been identified by calculating spatially distributed groundwater recharge as a function of land cover. Groundwater drought is defined by a threshold method. The results show that the evapotranspiration and rainfall deficits are determining meteorological drought, which shows a direct relation with groundwater recharge deficits. Land-cover change has a small effect on groundwater recharge but does not seem to be the main cause of groundwater-level decline (depletion) in the study area. The groundwater depth and groundwater-level deficit (drought) is continuously increasing with little correlation to meteorological drought or recharge anomalies. Overexploitation of groundwater for irrigation seems to be the main cause of groundwater-level decline in the study area. Efficient irrigation management is essential to reduce the growing pressure on groundwater resources and ensure sustainable water management. 相似文献
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At present, drought monitoring has changed from single factor to multi-factor comprehensive direction. In order to better promote the development of comprehensive drought monitoring theory and related models, the conceptual connotation of comprehensive drought monitoring was comprehensively and systematically analyzed, and the construction methods of comprehensive drought monitoring model were sorted out, which were divided into fivemethods Water balance model method, linear model combination method, multi-variable joint distribution function method, principal component analysis method and multi-source information data mining method. Furthermore, in view of the current challenges and shortcomings of integrated drought monitoring, the direction of future development of integrated drought monitoring model was put forward, that is, at the theoretical level: The first is to study the internal mechanism of drought and its occurrence and development process, clarify the relationship among the factors affecting drought, and construct a comprehensive quantitative drought monitoring model integrating multiple factors; The second is to enhance the pertinence of drought monitoring model, develop suitable drought monitoring model according to different regions, underlying surface, growing season, etc.;The third is to construct the precision verification index system of comprehensive monitoring model for drought in view of the difficulty of model validation. At the technical level, the integration and fusion of drought-related multi-source information is studied to improve its comprehensive utilization level and provide abundant data support and technical support for drought monitoring.
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This study presents a discriminant analysis-based method for prediction of agriculture drought disaster risk. We selected the Chaoyang city in the Northeast China as the study area. We employed multi-scale standard precipitation index (SPI) to reflect drought hazard. We used the yield losses to indicate the drought disaster risk, which was divided into no, low, or high drought risk. We used the multi-scale SPI and drought disaster risk as the input factors for the discriminant analysis-based risk prediction model. The results showed that the model’s prediction accuracy varied between 40 and 82.4 %. The accuracy of high drought disaster risk category was higher than low and no drought disaster risk category. The prediction accuracy of the milky maturity stage was highest. We use leave-one-out cross-validation method to validate the model’s accuracy. And the results showed that the model validation accuracy of high drought group could reach 70.6 % in milky maturity stage. This study showed discriminant analysis is an effective and operable method for disaster risk prediction. This model can provide timely information for decision makers to make effective measures for drought disaster management and to reduce the drought effects to yields at the minimum level. 相似文献
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干旱等级具有多级和跃迁性质,有必要提出一种既能反映不同干旱等级变化特征,又能体现干旱总体变化特征的定量评估方法。通过构建干旱等级变化的概率矩阵,引入变化率乘子和变化程度乘子,推导干旱等级变化率和变化程度计算公式,提出干旱等级变化的综合定量评估方法;借助标准化降水蒸散指数和标准化径流指数,应用于东江流域评估月、季和年尺度的气象干旱向水文干旱传递过程中干旱等级变化及水库影响下水文干旱等级变化。结果表明:①气象干旱向水文干旱传递过程中干旱总体变化程度较小,但干旱等级变化明显,月、季和年尺度的总体变化率分别达到了45.9%、46.8%和34.9%;②干旱在10月下降了约1.4个等级,在春季上升了约1.3个等级;③水库径流调节对于缓解月、季尺度水文干旱作用显著,干旱等级总体变化率均约为33%,其中春季干旱程度下降了约1个等级。该方法不仅适用于评估干旱变化,也可应用于评估具有分级特征的其他灾害变化。 相似文献
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Spatio-temporal Distribution of Three Kinds of Flash Droughts over Agricultural Land in China from 1983 to 2015 总被引：1，自引：0，他引：1
At present, flash drought occurs globally and regionally and causes a lot of socio-economic loss in a very short time. Therefore, flash drought has been regarded as one of the hottest issues in drought research. However, flash drought monitoring, prediction and decision-making have encountered a lot of challenges due to its multiple driven factors and complex spatio-temporal process. Aiming at this problem, this paper focused on the agricultural land in China, and analyzed the spatio-temporal distribution of three kinds of flash droughts (i.e., precipitation-deficit, high-temperature, and composite flash droughts) from 1983 to 2015. We studied the occurrences, duration, spatial distribution, temporal distribution, and trend of all three kinds of flash droughts. Our results demonstrated that, the occurrences of flash drought agricultural land in China increased year by year, among which high-temperature flash drought increased dramatically; duration of flash droughts had different trends, but the variations were relatively smooth; Northeast China was identified as a vulnerable area of flash drought, indicating more flash drought events and longer duration; flash droughts in China were found to concentrate in spring (high-temperature drought) and summer seasons (precipitation-deficit drought). This study is helpful for building new flash drought monitoring method and system, and it is also valuable for flash drought preparedness on regional scale. 相似文献
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利用黄河流域160个气象站1961-2010年逐日综合气象干旱指数(CI)指数, 对比分析两种用逐日CI指数判断月干旱过程的方法. 结果表明: 对重大干旱事件个例来说, 两种方法都能大体描述事件的月干旱过程, 但干旱的强度和范围有所不同. 从干旱发生的范围来看, 两种结果的差别较小, 方法I的识别结果范围更大、更连续, 特别是对青海旱情的判断常常比实际范围大;而方法II的识别结果范围稍小, 大体上能反应干旱的整体范围, 但有时也偶尔会遗漏小部分旱区;从干旱发生的强度来看, 方法I对干旱事实的描述偏轻, 而方法II以重-特旱为主, 与实际情况更相符. 从对黄河流域近50 a月干旱频率的分析结果来看, 两种方法一致表明黄河流域分界线以西的地区常年不容易发生干旱, 而对于分界线以东地区, 两种方法的统计结果有较大差异. 方法I的结果表明, 分界线以东地区干旱的月发生频率较大, 其中, 轻旱的月发生频率最大, 其次为中旱, 而重旱和特旱的发生频率很小;方法II的结果表明, 分界线以东地区干旱的月发生频率在60%~80%左右, 其中重旱的月发生频率最大, 其次为中旱, 轻旱和特旱的发生频率很小. 总体来说, 方法II对黄河流域月干旱情况的评估结果与干旱实际情况更一致. 相似文献
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应用土壤水模拟模型研究区域干旱 总被引：1，自引：1，他引：1
旨在应用平原地区土壤水模拟模型，给出区域旱精分析所需的干旱信息。以多年平均土壤含水量为判断旱情发生的临界函数，经过统计分析后，提出了一种适用于平原地区分析 区域旱情严重程度的实用方法和拟定评价旱情的定量标准。 相似文献
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Drought risk assessment in the western part of Bangladesh 总被引：14，自引：8，他引：6
Though drought is a recurrent phenomenon in Bangladesh, very little attention has been so far paid to the mitigation and preparedness
of droughts. This article presents a method for spatial assessment of drought risk in Bangladesh. A conceptual framework,
which emphasizes the combined role of hazard and vulnerability in defining risk, is used for the study. Standardized precipitation
index method in a GIS environment is used to map the spatial extents of drought hazards in different time steps. The key social
and physical factors that define drought vulnerability in the context of Bangladesh are identified and corresponding thematic
maps in district level are prepared. Composite drought vulnerability map is developed through the integration of those thematic
maps. The risk is computed as the product of the hazard and vulnerability. The result shows that droughts pose highest risk
to the northern and northwestern districts of Bangladesh. 相似文献
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强火山活动是气候变化的重要自然驱动因素,可导致中国降水出现年际或年代际变化,甚至极端的旱涝现象。探究位于中国邻域的印度尼西亚—菲律宾一带的强火山喷发与中国旱涝分布格局的关系,有助于阐释中国旱涝发生的时空规律及机制,为预测未来火山爆发可能导致的降水异常提供借鉴。本文基于1500—2000年期间世界强火山活动和中国旱涝资料,运用时序叠加分析的方法辨识了印度尼西亚—菲律宾一带的强火山喷发后中国旱涝在年际尺度上的时空变化特征,并对1815年Tambora火山喷发进行案例分析。结果表明印度尼西亚—菲律宾一带的强火山喷发对中国的旱涝格局有一定的影响:强火山喷发后第0年至第2年,中国中东部各站点的整体变化为偏涝;在第3年,整体出现了偏旱的转变,且变化幅度相比其他年份较大;就地区而言,喷发后华北、华南地区分别出现了由旱转涝、由涝转旱的变化,并且这些变化大概持续了2~3年,随后2个区域均恢复了喷发前的旱涝趋势;印度尼西亚1815年Tambora火山喷发后0~3年,中国以涝情为主,但发生涝情的区域逐年在发生变化。 相似文献