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111.
水文时间系列周期分析方法探讨 总被引:15,自引:2,他引:15
以分析广东省降水周期变化规律为例,探讨了最大熵谱方法在提取水文时间系列的主次周期上以及小波变换方法在分析水文时间系列的多时间尺度演变规律上的应用。由计算结果分析得到广东省降水过程主要存在的周期特性和旱涝变化趋势,为广东省降水趋势预测提供了重要信息。 相似文献
112.
川藏公路然乌—鲁朗段工程地质条件极其复杂,导致大型地质灾害频繁发生。为了定量地分析各种影响因素对大型地质灾害的贡献,本文根据信息熵的理论和方法,提出了“地质灾害熵”的概念。通过详细分析川藏公路然乌—鲁朗段大型地质灾害资料,选择平均坡度、断层和节理、岩体结构、松散堆积物、水文地质条件、冰川作用和降雨等7个影响因素,分析它们对研究区某些大型地质灾害的影响程度,计算出了各影响因素的“地质灾害熵”。根据“地质灾害熵”计算得到了各影响因素的权重,在一定程度上解决了地质灾害影响因素的定量分析问题。 相似文献
113.
In several LUCC studies, statistical methods are being used to analyze land use data. A problem using conventional statistical methods in land use analysis is that these methods assume the data to be statistically independent. But in fact, they have the tendency to be dependent, a phenomenon known as multicollinearity, especially in the cases of few observations. In this paper, a Partial Least-Squares (PLS) regression approach is developed to study relationships between land use and its influencing factors through a case study of the Suzhou-Wuxi-Changzhou region in China. Multicollinearity exists in the dataset and the number of variables is high compared to the number of observations. Four PLS factors are selected through a preliminary analysis. The correlation analyses between land use and in-fluencing factors demonstrate the land use character of rural industrialization and urbaniza-tion in the Suzhou-Wuxi-Changzhou region, meanwhile illustrate that the first PLS factor has enough ability to best describe land use patterns quantitatively, and most of the statistical relations derived from it accord with the fact. By the decreasing capacity of the PLS factors, the reliability of model outcome decreases correspondingly. 相似文献
114.
José Carlos de Araújo 《地球表面变化过程与地形》2007,32(13):2005-2018
A new equation to assess hillslope sediment production, based on physical and probabilistic approaches, is presented. The equation, which allows the computation of the delivery ratio for every event, considers the physical variables of travel distance, stream power, settling velocity and gross erosion. The probability density function that arises from the new formulation is solved using the principle of maximum entropy. Based on data from five watersheds in both tropical and temperate zones, the new delivery parameter Kv is calibrated and associated with vegetation cover and conservation practice. The proposed equation is rationally based in relation to parameter Kv. The entropy‐based equation was applied to assess sediment yield in two other experimental watersheds, showing good predictability for the set (mean absolute error of 20·8%). No systematic error was found in the analysed data. The entropy‐based equation showed good predictability for long‐term sets of data and for high‐erosivity events, but did not perform well for the low‐erosivity ones. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
115.
基于MEM1谱分析的水文时间序列隐含周期特性研究 总被引:13,自引:1,他引:13
水文时间序列的隐含周期(本文将简单周期、复合周期及近似周期等统称为隐含周期)的识别、判定是一个重要而又较为困难的问题,相对成熟和有效的做法是对其进行频谱分析。建立在最大熵原理(POME)基础之上的MEM1谱分析,克服了传统谱分析方法的诸多不足,具有频谱光滑、分辨率高等独特优势。为此,以黄河花园口(秦厂)测站年径流系列、月径流系列和年最大洪峰流量序列隐含周期特性的研究为例,探讨了MEM1谱分析在水文时间序列隐含周期特性中的应用。 相似文献
116.
论证“熵气象学”就是应用热力学第二定律的动力气象,是不足是统计出来的规律,所以它是气象学的发展。 相似文献
117.
地下水观测网的若干问题与基于信息熵的研究方法 总被引:5,自引:0,他引:5
观测站点分布的任意性、随意性和层次不清以及观测数据的冗余性等是中国地下水观测网普遍存在的问题 ,这些问题制约着观测网提供可靠和有效数据信息的能力。文章以河北平原地下水观测网为例 ,分析了观测网几个问题的表现和原因 ,并对国内外观测网优化设计的指导思想、技术方法的现状和进展作了简要介绍。在参考大量国内外研究成果的基础上 ,主要介绍了基于信息熵原理研究观测网优化设计的方法 ,包括基本概念、原理和解决观测孔层次分类、信息冗余以及空间优化布局的技术思想。笔者认为 ,信息熵方法是一种能够评价地下水观测网信息 (而不是数据 )收集能力和优化观测网布局的很具发展潜力的技术方法。 相似文献
118.
Partial melting in the Inzie Head gneisses: the role of water and a petrogenetic grid in KFMASH applicable to anatectic pelitic migmatites 总被引:5,自引:0,他引:5
A sequence of prograde isograds is recognized within the Dalradian Inzie Head gneisses where pelitic compositions have undergone variable degrees of partial melting via incongruent melting reactions consuming biotite. Three leucosome types are identified. At the lowest grades, granitic leucosomes containing porphyroblasts of cordierite (CRD‐melt) are abundant. At intermediate grades, CRD‐melt mingles with garnetiferous leucosomes (GT‐melt). At the highest grades, CRD‐melt coexists with orthopyroxene‐bearing leucosomes (OPX‐melt), while garnet is conspicuously absent. The prograde metamorphic field gradient is constrained to pressures of 2–3 kbar below the CRD‐melt isograd, and no greater than 4.5 kbar at the highest grade around Inzie Head. A petrogenetic grid, calculated using thermocalc , is presented for the K2O–FeO–MgO–Al2O3–SiO2–H2O (KFMASH) system for the phases orthopyroxene, garnet, cordierite, biotite, sillimanite, H2O and melt with quartz and K‐feldspar in excess. For the implied field gradient, the reaction sequence predicted by the grid is consistent with the successive prograde development of each leucosome type. Compatibility diagrams suggest that, as anatexis proceeded, bulk compositions may have been displaced towards higher MgO content by the removal of (relatively) ferroan granitic leucosome. An isobaric (P = 4 kbar) T–aH2O diagram shows that premigmatization fluids must have been water‐rich (aH2O > 0.85) and suggests that, following the formation of small volumes of CRD‐melt, the system became fluid‐absent and melting reactions buffered aH2O to lower values as temperatures rose. GT‐ and OPX‐melt formed by fluid‐absent melting reactions, but a maximum of 7–11% CRD‐melt fraction can be generated under fluid‐absent conditions, much less than the large volumes observed in the field. There is strong evidence that the CRD‐melt leucosomes could not have been derived by buoyantly aided upwards migration from levels beneath the migmatites. Their formation therefore required a significant influx of H2O‐rich fluid, but in a quantity insufficient to have exhausted the buffering capacity of the solid assemblage plus melt. Fluid : rock ratios cannot have exceeded 1 : 30. The fluid was channelled through a regionally extensive shear zone network following melt‐induced failure. Such an influx of fluid at such depths has obvious consequences for localized crustal magma production and possibly for cordierite‐bearing granitoids in general. 相似文献
119.
近30年我国气候变化的不稳定性及其与农业生产的关系 总被引:6,自引:0,他引:6
引入信息论中熵值分析方法,利用全国七大区1961-1990年的气象和产量资料,讨论了近年平均气温,最高气温,最低气温和降水量的熵值时空变化类型。详细分析了我国气候变化的不稳定性,在此基础上,定性讨论了气候波动与农业气象灾害的关系及其对农业产量的影响,并分区建立了产量与气象要素熵的回归模型。 相似文献
120.
IntroductiontoanInvariantQuantityMethodLiuGuifu(刘桂复)(NamingInstituteofMeteorology,Naming210044ReceivedMarch11.1995,revisedJun... 相似文献