Research on runoff variations based on wavelet analysis and wavelet neural network model: A case study of the Heihe River drainage basin (1944?2005)     

WANG Jun  MENG Jijun 《地理学报》2007,17(3):327-338

The Heihe River drainage basin is one of the endangered ecological regions of China. The shortage of water resources is the bottleneck, which constrains the sustainable development of the region. Many scholars in China have done researches concerning this problem. Based on previous researches, this paper analyzed characteristics, tendencies, and causes of annual runoff variations in the Yingluo Gorge (1944–2005) and the Zhengyi Gorge (1954–2005), which are the boundaries of the upper reaches, the middle reaches, and the lower reaches of the Heihe River drainage basin, by wavelet analysis, wavelet neural network model, and GIS spatial analysis. The results show that: (1) annual runoff variations of the Yingluo Gorge have principal periods of 7 years and 25 years, and its increasing rate is 1.04 m3/s·10y; (2) annual runoff variations of the Zhengyi Gorge have principal periods of 6 years and 27 years, and its decreasing rate is 2.25 m3/s·10y; (3) prediction results show that: during 2006–2015, annual runoff variations of the Yingluo and Zhengyi gorges have ascending tendencies, and the increasing rates are respectively 2.04 m3/s·10y and 1.61 m3/s·10y; (4) the increase of annual runoff in the Yingluo Gorge has causal relationship with increased temperature and precipitation in the upper reaches, and the decrease of annual runoff in the Zhengyi Gorge in the past decades was mainly caused by the increased human consumption of water resources in the middle researches. The study results will provide scientific basis for making rational use and allocation schemes of water resources in the Heihe River drainage basin.  相似文献   

遥测降雨抗差分析方法应用研究     

李荣容  包为民 《水文》2007,27(6):25-27,21

遥测系统观测的雨量资料常会包含粗差，根据降雨量的特征，结合抗差理论，包为民等曾提出三步抗差修正方法。将此法应用到龙颈上水库等10个水库流域的实测资料当中，验证其有效性，并分析比较各步抗差修正的效果及降雨特征与抗差效果之间的关系。结果表明，抗差修正方法可行，且第一步和第三步结合的修正效果最好；降雨中心较明确，多年降雨特征相似，强度变幅稳定的洪水，不容易出现误抗。  相似文献   

近50年来新疆天山山区水循环要素的变化特征与趋势   总被引：2，自引：0，他引：2  

蓝永超  吴素芬  钟英君  韩萍  赵琪 《山地学报》2007,25(2):177-183

天山山区由于其特殊的地理位置与高海拔,成为新疆地表径流的主要产流区域。近几十年来,全球平均气温的持续上升对该区域气温、降水、径流等水循环要素产生重要的影响。根据天山南北坡有关水文气象台站的观测资料,系统地分析了该区域1960年代以来各水循环要素的变化特征与趋势。结果表明,受全球变暖的影响,1980年以来整个天山地区气温和降水均呈明显的上升趋势,其中10 a气温的升幅更为显著;对于降水而言,天山南坡降水增幅大于北坡,而南坡的西段是近10 a降水增幅最大的区域。受气温上升与降水增加的影响,天山地区出山径流总体上呈增加的趋势,其中,近10 a天山南坡中西段河流出山径流量增幅最为显著,平均增幅在30%以上。  相似文献   

胶东山丘区典型流域径流年内分配特征量化研究     

刘德林  刘贤赵  李嘉竹  宿庆 《山地学报》2007,25(3):295-301

采用M ann-Kendall法和最小方差法,对大沽夹河流域1966~2004年逐月实测径流数据进行均值变点分析。根据分析结果,将径流划分为水文变化特征相似的A(1966~1971年)、B(1972~1981年)、C(1982~1996年)、D(1997~2004年)4个时段。在此基础上借鉴年降水年内分配的向量法,提出了量化径流年内分配的集中度和集中期。结果表明:1.大沽夹河的不同水文年,其径流年内分配的特征不同。时段A集中度最小,时段D最大,4个时段变差系数为0.12。时段A和时段C的集中期比较接近,最大径流出现的时间均在7月下旬,时段B和时段D的集中期比较相似,最大径流出现的时间在8月中下旬。径流年内分配与降水年内分配两者呈显著正相关。2.用月径流量计算的集中度比径流年内不均匀系数具有更高的分辨能力和有效性,用月径流量计算的集中期对应的月份与月径流最大值出现的实际月份完全一致,径流集中度、集中期能够充分定量地表征径流在年内分配的非均匀性。  相似文献   

Study on snowmelt runoff simulation in the Kaidu River basin     

ZHANG YiChi  LI BaoLin  BAO AnMing  ZHOU ChengHu  CHEN Xi  ZHANG XueRen 《中国科学D辑(英文版)》2007,50(Z1):26-35

Alpine snowmelt is an important generation mode for runoff in the source region of the Tarim River basin, which covers four subbasins characterized by large area, sparse gauge stations, mixed runoff supplied by snowmelt and rainfall, and remarkably spatially heterogeneous precipitation. Taking the Kaidu River basin as a research area, this study analyzes the influence of these characteristics on the variables and parameters of the Snow Runoff Model and discusses the corresponding determination strategy to improve the accuracy of snowmelt simulation and forecast. The results show that: (i) The temperature controls the overall tendency of simulated runoff and is dominant to simulation accuracy, as the measured daily mean temperature cannot represent the average level of the same elevation in the basin and that directly inputting it to model leads to inaccurate simulations. Based on the analysis of remote sensing snow maps and simulation results, it is reasonable to approximate the mean temperature with 0.5 time daily maximum temperature. (ii) For the conflict between the limited gauge sta-tion and remarkably spatial heterogeneity of rainfall, it is not realistic to compute rainfall for each elevation zone. After the measured rainfall is multiplied by a proper coefficient and adjusted with runoff coefficient for rainfall, the measured rainfall data can satisfy the model demands. (iii) Adjusting time lag according to the variation of snowmelt and rainfall position can improve the simulation precision of the flood peak process. (iv) Along with temperature, the rainfall increases but cannot be completely monitored by limited gauge stations, which results in precision deterioration.  相似文献   

DWEPP: a dynamic soil erosion model based on WEPP source terms     

N. S. Bulygina  M. A. Nearing  J. J. Stone  M. H. Nichols 《地球表面变化过程与地形》2007,32(7):998-1012

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Peak runoff contributing area as hydrological signature of the probability distribution of floods     

Mauro Fiorentino  Salvatore Manfreda  Vito Iacobellis 《Advances in water resources》2007

For the analysis of hydrological extremes and particularly in flood prediction, deeper investigation is needed on the relative effects of different hydrological processes acting at the basin scale in different hydroclimatic areas of the world. In this framework, the theoretical derivation of flood distribution shows a great potential for development and knowledge advancement. In addition, another promising path of investigation is represented by the use of distributed hydrological models via simulation modelling (including Monte Carlo, discrete event and continuous simulation). In this paper results of a theoretically derived flood frequency distribution are analyzed and compared with the results of a simulation scheme that uses a distributed hydrological model (DREAM) in cascade with a rainfall generator (IRP). The numerical simulation allows the reproduction of a large number of extreme events and provides insight into the main control for flood generation mechanisms with particular emphasis to the peak runoff contributing areas, highlighting the relevance of soil texture and morphology in different climatic environments. The proposed methodology is applied here to the Agri and the Bradano basin, in Southern Italy.  相似文献   

地形引起的雷达辐射畸变及其校正   总被引：3，自引：3，他引：3  

张永红  张继贤  林宗坚  高武俊 《测绘科学》2002,27(4):23-26

合成孔径雷达影像由于其侧视特点 ,存在着严重的地形引起的几何畸变及辐射畸变。辐射畸变不仅对 SAR辐射标定造成困难 ,而且严重影响了影像分类、土壤湿度信息提取、森林蓄积量信息提取等应用。本文将辐射畸变归结为面积效应和局部入射角效应 ,推导了散射面积归一化因子 ,以消除辐射畸变的面积效应。提出了一种以局部入射角的线性函数表达的后向散射模型 ,在此基础上 ,给出了消除局部入射角效应的校正函数。最后 ,以RADARSAT SAR影像进行地形辐射畸变校正的试验与分析  相似文献   

相位激电法(偶极-偶极)单频电磁耦合校正方法   总被引：2，自引：2，他引：2  

王书民  雷达 《物探与化探》2002,26(1):57-59,63

主要介绍一种相位激电法(偶极—偶极,以下简称偶极)电磁耦合校正方法,其原理是将视电阻率近似视为均匀大地电阻率,利用均匀大地条件下偶极装置电磁感应响应的正演计算方法,算出电磁感应响应,再将其从观测的总响应中去除,从而达到电磁耦合校正的目的。  相似文献   

重力中区地形改正系统的研制   总被引：1，自引：1，他引：1  

冯治汉 《物探与化探》2002,26(6):467-469

从传统的重力地形改正方法入手,用Delphi语言编制了Windows程序,使得多年来重力中区地形改正繁重的手工数图工作能够用计算机完成,且计算精度得到明显提高。最后用甘肃1:20万昌马幅的53个重力测点进行了试算。  相似文献