Impact of climate change on 24‐h design rainfall depth estimation in Qiantang River Basin,East China     

Yue‐Ping Xu  Xujie Zhang  Ye Tian 《水文研究》2012,26(26):4067-4077

The frequency and magnitude of extreme meteorological or hydrological events such as floods and droughts in China have been influenced by global climate change. The water problem due to increasing frequency and magnitude of extreme events in the humid areas has gained great attention in recent years. However, the main challenge in the evaluation of climate change impact on extreme events is that large uncertainty could exist. Therefore, this paper first aims to model possible impacts of climate change on regional extreme precipitation (indicated by 24‐h design rainfall depth) at seven rainfall gauge stations in the Qiantang River Basin, East China. The Long Ashton Research Station‐Weather Generator is adopted to downscale the global projections obtained from general circulation models (GCMs) to regional climate data at site scale. The weather generator is also checked for its performance through three approaches, namely Kolmogorov–Smirnov test, comparison of L‐moment statistics and 24‐h design rainfall depths. Future 24‐h design rainfall depths at seven stations are estimated using Pearson Type III distribution and L‐moment approach. Second, uncertainty caused by three GCMs under various greenhouse gas emission scenarios for the future periods 2020s (2011–2030), 2055s (2046–2065) and 2090s (2080–2099) is investigated. The final results show that 24‐h design rainfall depth increases in most stations under the three GCMs and emission scenarios. However, there are large uncertainties involved in the estimations of 24‐h design rainfall depths at seven stations because of GCM, emission scenario and other uncertainty sources. At Hangzhou Station, a relative change of ?16% to 113% can be observed in 100y design rainfall depths. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

PRINCIPES FONDAMENTAUX DE LA THEORIE DU MOUVEMENT DES EAUX SOUTERRAINES     

A. N. BELANY 《水文科学杂志》2013,58(1):14-21

ABSTRACT

In southeastern Arizona, almost all summer rainfall results from widely-scattered high-intensity afternoon or evening thunderstorms of limited areal extent. For eleven years of record on the Walnut Gulch Experimental Watershed, Tombstone, Arizona, about 70 percent of the annual rainfall of 11 1/2 inches and over 95 percent of the annual runoff occurred in July, August, and early September. In contrast, about 5 percent of the rainfall occurred in the previous 3 months, and about 25 percent in the remaining 6 1/2 months.

Therefore, summer rainfall, although highly variable, represented the most dependable source of water to the Walnut Gulch watershed. On the average, significant rainfall was recorded on some part of the watershed on 40 percent of the days in the critical July-August period. The maximum frequency was 3 out of every 4 days in 1955, and the minimum 3 out of every 10 days in 1960.

The wettest year was 1955, with a continuous rainy period of 47 days; whereas, the driest was 1960, with the longest rainy period lasting only 5 days. The longest summer drought during the period of record occurred in 1962, when no rain fell for 17 days in August, following a 14-day rainy period in late July.

As yet, there are not enough data to determine reliable expectancies for summer rainy or drought periods.  相似文献   

Assessing uncertainties in a conceptual water balance model using Bayesian methodology / Estimation bayésienne des incertitudes au sein d’une modélisation conceptuelle de bilan hydrologique     

《水文科学杂志》2013,58(1)

Abstract

Abstract The aim of this study was to estimate the uncertainties in the streamflow simulated by a rainfall–runoff model. Two sources of uncertainties in hydrological modelling were considered: the uncertainties in model parameters and those in model structure. The uncertainties were calculated by Bayesian statistics, and the Metropolis-Hastings algorithm was used to simulate the posterior parameter distribution. The parameter uncertainty calculated by the Metropolis-Hastings algorithm was compared to maximum likelihood estimates which assume that both the parameters and model residuals are normally distributed. The study was performed using the model WASMOD on 25 basins in central Sweden. Confidence intervals in the simulated discharge due to the parameter uncertainty and the total uncertainty were calculated. The results indicate that (a) the Metropolis-Hastings algorithm and the maximum likelihood method give almost identical estimates concerning the parameter uncertainty, and (b) the uncertainties in the simulated streamflow due to the parameter uncertainty are less important than uncertainties originating from other sources for this simple model with fewer parameters.  相似文献   

Uncertainty,entropy, scaling and hydrological stochastics. 1. Marginal distributional properties of hydrological processes and state scaling / Incertitude,entropie, effet d'échelle et propriétés stochastiques hydrologiques. 1. Propriétés distributionnelles marginales des processus hydrologiques et échelle d'état     

《水文科学杂志》2013,58(3)

Abstract

The well-established physical and mathematical principle of maximum entropy (ME), is used to explain the distributional and autocorrelation properties of hydrological processes, including the scaling behaviour both in state and in time. In this context, maximum entropy is interpreted as maximum uncertainty. The conditions used for the maximization of entropy are as simple as possible, i.e. that hydrological processes are non-negative with specified coefficients of variation (CV) and lag one autocorrelation. In this first part of the study, the marginal distributional properties of hydrological variables and the state scaling behaviour are investigated. Application of the ME principle under these very simple conditions results in the truncated normal distribution for small values of CV and in a nonexponential type (Pareto) distribution for high values of CV. In addition, the normal and the exponential distributions appear as limiting cases of these two distributions. Testing of these theoretical results with numerous hydrological data sets on several scales validates the applicability of the ME principle, thus emphasizing the dominance of uncertainty in hydrological processes. Both theoretical and empirical results show that the state scaling is only an approximation for the high return periods, which is merely valid when processes have high variation on small time scales. In other cases the normal distributional behaviour, which does not have state scaling properties, is a more appropriate approximation. Interestingly however, as discussed in the second part of the study, the normal distribution combined with positive autocorrelation of a process, results in time scaling behaviour due to the ME principle.  相似文献   

地下储层表征的不确定性及科学思维方法     

吴胜和  杨延强 《地球科学与环境学报》2012,(2):72-80

由于地质的复杂性和资料的不完备性,地下储层表现为“灰箱”系统,表征结果存在着不确定性.基于系统论和科学哲学的方法,探讨了地下储层表征中不确定性的成因类型、内涵及解决方案,并论述了地下储层表征过程中所应重视的科学思维方法.地下储层表征中存在两类基本的不确定性类型:①随机不确定性,主要由局部预测整体(如应用多井资料进行井间储层预测)以及第二性资料的非完全映射(如应用地震资料预测储层)所致;②模糊不确定性,主要由储层概念模式认知不足所致.为了使表征结果逼近地质实际,除了正确应用和创新相关理论和方法外,需要具备科学的表征理念和思维,包括总体把握、分级约束,多科一体、地质为核,发散求索、聚焦论证,辩证思维、综合分析;同时,应正确理解和处理宏观与微观、绝对与相对、静态与动态、映射与多解、局部与整体、模糊与置信、确定与随机、个别与一般、复杂与简约、手工与自动等矛盾统一体的关系.  相似文献   

近40年来中国大陆地表气温变化估算     

孙朝阳  邵全琴  刘纪远 《地球信息科学学报》2012,14(1):14-21

 本文对近20年来中国地表气温变化估算方法进行了全面的总结,并对不同研究者所采用的资料、时间尺度及研究结果进行了对比分析。结合当前国际上应用较多的几种升温估算方法,本文以1970-2007年的气温数据为基础,分别应用直接算术平均法、逐站计算法、区域面积加权法、一级差分法和空间插值法,对中国大陆近40年的升温幅度分别进行了估算,从结果的对比分析中揭示中国地表气温变化估算中存在的不确定性:中国大陆地区近40年来的增温趋势在0.30~0.43℃/10a之间,升温幅度在1.16~1.56℃之间;冬季升温最为显著,夏季升温最少;整体上北方升温幅度高于南方。不同计算方法计算得到的增温速率在绝对值上有着一定差异,但整体趋势是相同的。  相似文献   

贝叶斯网络在水资源管理中的应用   总被引：3，自引：0，他引：3  

卢文喜  罗建男  鲍新华 《吉林大学学报(地球科学版)》2011,41(1):153-158

为了解决水资源管理中具有不确定性的多目标决策问题,将贝叶斯网络方法引入水资源管理中。通过对实例系统中变量间相互关系的分析,构建描述变量间不确定性关系的贝叶斯网络模型,其中包括表示其依赖关系的有向无环图和表示其具体概率依赖程度的条件概率表,并在6个目标变量均达到预期目标的前提下进行概率推理。实例结果表明：当补偿款数额增加到500元/亩时,所有的目标变量均可达到最优,因此确定出政府应给农民补偿款的数额为500元/亩的合理水资源决策方案。贝叶斯网络以图模型的方式直观地表达了实例系统中变量之间的不确定性关系,概率推理的结果兼顾了环境效益以及农民的利益,使多个预期目标均达到了最优,有效地解决了水资源管理中具有不确定性的多目标决策问题。  相似文献   

Land Use Allocation Based on Interval Multi-objective Linear Programming Model： A Case Study of Pi County in Sichuan Province   总被引：3，自引：1，他引：2  

Hongrui Wang  Yuanyuan Gao  Qiong Liu  Jinxi Song 《中国地理科学(英文版)》2010,20(2):176-183

Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was established and applied to analyzing the suitability of land use structure in Pi County of Sichuan Province. An adjustment scheme for optimizing land use structure was proposed on the basis of development planning drawn up by the local government. The results are summarized as follows: 1) the opti...  相似文献   

潜在震源区震级上限不确定性研究   总被引：7，自引：1，他引：6  

冉洪流 《地震学报》2009,31(4):396-402

潜在震源区的震级上限（Mu）是指在该潜在震源区内可能发生的最大地震的震级．预期未来发生超过该震级地震的概率趋于0．本文运用误差分析及逻辑树等方法,并结合发震模型的数值模拟得到的大震合成目录等结果,系统分析并最终得到了不同途径给出的不同类型潜在震源区震级上限的不确定性．该结果可直接应用于包括地震区划在内的工程地震以及活动断裂危险性评价等工作中．   相似文献   

基于GIS矿产勘查靶区优选技术   总被引：1，自引：0，他引：1  

夏庆霖  成秋明  左仁广  张生元  陈志军 《地球科学》2009,34(2):287-293

靶区优选是矿产勘查中的一个关键环节, 它既是矿产资源预测成果的直接体现形式, 同时又是联系矿产资源预测与勘查工作部署的桥梁.然而, 由于人们认识上的不完备性和缺乏相应的技术手段支撑, 使得靶区优选常被忽视或简化.探讨了靶区优选的地质基础原则, 建立了靶区优选的技术流程, 研发了基于GIS支持下靶区优选计算机辅助决策模块, 并以云南省个旧地区与岩浆活动有关的锡铜多金属矿靶区为例进行了示范研究.结果表明靶区优选技术及相应的软件能够客观地反映不同靶区的特征, 提高靶区优选的智能化程度和工作效率.   相似文献