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Cédric Gaucherel Romain Frelat Audrey Lustig Bastien Rouy Yvelt Chéry Pierre Hubert 《水文科学杂志》2013,58(2):274-288
AbstractComprehensive characterization of its flow rates is prerequisite to a proper understanding and water management of a given hydrological region. Several studies question the soundness of stationarity in time series and suggest the need for a quantification of the events and non-stationary features in flow rate time series. In this study, we combine statistical and time–frequency (TF) analyses to characterize and classify the flow rates of an understudied region, namely Haiti. Wavelet transforms and cyclostationarity analyses were combined with principal component analysis and hierarchical clustering to identify three groups of hydrological regimes in the country, suggesting similar management: (1) relatively stable flow rates with TF behaviour; (2) periodic and strongly seasonal flow rates; and (3) unstable flow rates. We argue that the TF methodology can yield additional information in regard to flow events and multiscale behaviour, even for short records. Flow rate characterization would benefit from the exhaustive approach described here.
EDITOR Z.W. Kundzewicz ASSOCIATE EDITOR E. Toth 相似文献
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关于地质灾害孕灾因子权重确定的探讨 总被引:3,自引:0,他引:3
地质灾害易发区划模型中,不同地区孕灾因子权重不同。因子权重的确定、求解权重的准确性将直接关系到区划结果的可靠度。本文根据地质灾害点在不同孕灾因子分区中的分布频率,推出不同孕灾因子对地质灾害发育的贡献率的相对大小。不同因子对地质灾害发育的贡献率实际上就是各因子在地质灾害易发模型中的权重,因此通过以上分析可得出不同孕灾因子的相对权重,再利用层次分析法(AHP法)得出孕灾因子的权重。通过统计分析得出各因子相对权重的方法弥补了层次分析法确定权重的人为随意性,提高了区划的准确度。 相似文献
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在综合考虑气候、植被、地貌等凶素的基础上,提出一种基于多层次格网模型的最近邻指数-模糊聚类生态区域划分算法(Nearest Neighbor Index Fuzzy clustering,NNI-FIC).该算法采用"自下而上"的方式,首先,利用离散格网单元之间的严格相似性形成区划的核心分区;然后,通过最近邻指数统计分... 相似文献
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Research and compilation of the Geomorphologic Atlas of the People’s Republic of China (1:1,000,000)
CHENG Weiming ZHOU Chenghu CHAI Huixia ZHAO Shangmin LIU Haijiang ZHOU Zengpo 《地理学报》2011,21(1):89-100
Geomorphologic maps are one of the most fundamental materials of the natural environment. They have been widely used in scientific research, resource exploration and extraction, education and military affairs etc. An editorial committee was established in 2001 to collect materials for researching and compiling a set of new 1:1,000,000 geomorphologic atlas of China. A digital geomorphologic database was created with visual interpretation from Landsat TM/ETM imageries and SRTM-DEM etc. The atlas compiled from the database was finished. The main characteristics of the atlas are as follows: Firstly, Landsat TM/ETM imageries, published geomorphologic maps or sketches, geographical base maps, digital geological maps, and other thematic maps were collected, which were uniformly geometrically rectified, clipped into uniform sheets, and stored in the foundation database. Secondly, based on the legends of 15 sheets 1:1,000,000 maps published in the 1980s, a geomorphologic classification system was built by combining morphology and genesis types. The system comprised seven hierarchical layers: basic morphology, genesis, sub-genesis, morphology, micro-morphology, slope and aspect, material composition and lithology. These layers were stored in the database during visual image interpretation. About 2000 kinds of morpho- genesis and 300 kinds of morpho-structure were interpreted. Thirdly, the legend system was built, which included color, symbol bases and note bases etc., compilation standards and procedures were developed, 74 sheets of 1:1,000,000 covering all land and sea territories of China were compiled, the 1:1,000,000 geomorphologic atlas of the People’s Republic of China was finished and published. The atlas will fill the blanks in national basic scale thematic maps, and the geomorphologic database could be applied widely in many fields in the future. 相似文献
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新疆地貌区划的一个新方案 总被引:3,自引:1,他引:2
在分析总结和借鉴继承前人地貌区划工作的基础上,开展新疆地貌区划研究.首先认为地貌区划既是对地貌划分的结果,也是地貌划分的方法与过程,同时还是认识地貌特征和发现地貌规律的一种科学方法.第二,确定新疆地貌区划的主要原则为区域性原则和等级系统原则,选择自下而上的类型合并与自上而下的区域分割相结合,协调使用的区划方法.第三,在区划原则和区划方法的指导下,对新疆地貌类型分布规律进行定性与定量研究,提出基于遥感和GIS技术的新疆地貌区划新方案,将新疆分为6个地貌区、23个地貌亚区和195个地貌小区.结果表明,该地貌区划方案能够体现出新疆各地貌类型及其分布格局,并具有区划等级的系统性,地貌分区的完整性,以及区划界线的准确性等特点. 相似文献