【作者】 周祥林；

【导师】 陆宝宏；

【作者基本信息】 河海大学 ， 水文学及水资源， 2006， 硕士

【摘要】 随着经济的发展,人口的增加,人类活动和降水时空分布不均等导致了旱灾发生的频率越来越高,旱灾对社会经济的发展和人民生活产生了巨大的影响。干旱威胁始终存在,损失巨大。如何准确、全面地描述干旱问题及科学评价其损失,分析其风险,成为十分紧迫而又必须解决的问题。本文以太湖流域为研究区域,分析研究了常用基于降雨的干旱指标在太湖流域中的适用性,针对常规干旱指标存在的缺点,根据流域雨量站的降雨特征、下垫面组成及站点分布等信息,通过聚类算法划分响应单元,以响应单元中的点雨量信息替代响应单元雨量信息,构建了基于响应单元的非参数统计流域气象干旱指标模型,以太湖流域的实际资料验证了构建模型的实用性。首先在全流域选取了12个代表站,计算各站的干旱指标值,再依据各站的权重,将其转换成流域的面干旱指标,根据太湖流域的实际旱情记录结果拟定干旱指标的等级区间。将流域按水资源分区原则分成四个三级区域,在每个区域中依据聚类分析法选取代表站,通过模型计算求出各区域历年的干旱指标值,统计分析各区的干旱特征,结果显示浙西区发生干旱的频率最高,而且发生中旱的频率也最大,受干旱影响的程度大,湖西区次之,黄埔区最小;从干旱发生的年代分布来看,黄埔区受旱的频率呈降低趋势。本文对四个区域进行区域干旱遭遇分析,其中湖西区和黄埔区同时受旱的可能性最小,浙西区和湖西区之间可能性最大。太湖流域干旱发生的季节主要集中在夏秋两季。其中夏季发生的频率最高,秋季次之,出现季节连旱的可能性较小。 通过非参数统计建立的干旱指标的精度比较高,在一定条件下可以应用到太湖流域中,被防汛抗旱部门用来指导抗旱工作。更多还原

【Abstract】 The frequency where happen flood and drought is very high in China. along with economic development, population increment and precipitation distribution imbalance, the frequency is more and more high. Regional or basin drought strongly depends on precipitation, temperature, physiographic characteristics, composition of plants and other factors. Due to the limitation of data, the factors mentioned above can’t be considered in analysis and evaluation models, so we must catch the most important factor which can result in drought. A method in terms of splitting response unit in the study basin, nonparametric estimation method incorporated with wandering analysis theory were presented to study on the regional drought index, by means of point drought index to evaluate are al drought was presented, and was used to evaluate the historical drought situation in the paper.In terms of the features of rainfall station, selected the data series of 12 rainfall staions by cluster analysis system, then calculated the drought index of these stations, which can be transformed to areal drought index basised on the weight of the stations, obtained the rate zones of drought index trought comparing to practical drought. Splited the basin to four zones, calculated the drought index of the typical stations from 1951—1990, anaylsised the drought peculiarity of the four zones. The degree which is affected by drought is most serious in Zhexi zone, Huxi zone is subsequent, Huangpu zone is the least. The paper anaylsed the probability of areal drought encounter of the four zones, the probability of taking place drought at the same time is the largest between Zhexi zone and Huxi zone. The mass of the drought events in Taihu basin take place in summer and autumn, the probability which there happen drought persisting more than two seasons is very low.The nonparametric estimation drought index is receivability for Taihu basin.The evaluation method of the nonparametric estimation can be widely used to assessdrought situation during face stage in Taihu Basin.更多还原