基于小波与R/S方法的汉江中下游流域降水量时间序列分析

基于汉江中下游流域9个国家气象站1961～2006年的降水数据,综合采用Morlet小波分析、小波分解和R/S分析方法,对流域降水量周期和未来趋势进行分析及预测。研究结果表明:汉江中下游流域年降水量存在5年左右的短周期和10～15年的中长周期;部分气象站可能存在40年左右长周期,需要更长的时间序列验证。基于通过小波分解提取的历史降水量变化趋势,进一步结合R/S分析表明,汉江中下游流域降水量时间序列总体上存在比较明显的赫斯特现象,未来该流域面临较大的防洪压力。     

Identifying and assessing the residency effect in Pocatello,Idaho, using combined census and parcel data

Human residency is the spatial effect source on ecosystem and thus it should be studied and assessed. Supporting residency effect research, this study developed and applied procedures and a model to combine census and parcel data for the assessment. The case study is in Pocatello, Idaho, where revealing land service associated with flood control and locating/evaluating resident effect are needed. Methods include (1) data mining, (2) land service valuation, (3) data screening, (4) integration of census and parcel data, (5) data screening, and (5) analysis and modeling with R programing language and ArcMap. Results are, for land service assessment, land value per area unit in residence areas (LAND) along the concrete channel (for flood control) was less than that along the Portneuf River. Spatial responses under LAND to a source effect (either the concrete channel or the river) are the same. The applied methods helped locate and assess a variety of residency effects spatio-temporally. Results informed the human preferences under LAND and the effect distribution to support decision-making. Technically, using the parcels as a baseline provided comprehensive results with a fine resolution for the effect study, particularly as combined with the census data. This study suggests using a data screening and validation procedure besides the mining approach to minimize outcome uncertainty.     

Seismic Wave Propagation and Excitation in Multi-layered Media with Irregular Interfaces Part (Ⅰ): SH Case

Study of seismic wave excitation and propagation in laterally heterogeneous media was an active and important subject in seismology in the past two decades, numerous analytical and numerical efforts have been made in this research field. In this article, I have, first, made a brief review on those developments and then introduced and summarized a unified and efficient method, global generalized reflection-transmission (abbreviated to R/T thereafter) matrices method, for synthetic seismograms in multi-layered media with irregular interfaces developed by the author [24~26]. As demonstrated in this article, this method could be regarded as an extension of the generalized R/T coefficients method for the horizontally layered case [2,5] to the layered media with irregularly shaped interfaces by incorporating the T matrices technique [27,28]. Because of the use of a recursive scheme in computing the global generalized R/T matrices, this method is efficient, particularly for the case with a large number of irre     

原子Na的电子碰撞电离

使用Ｒ矩阵方法, 在扭曲波和库仑玻恩近似下计算了入射电子能量为２０ ｅＶ、５０ｅＶ 及１００ ｅＶ 原子Ｎａ 的电子碰撞电离截面, 并详细给出了入射电子能量为５０ ｅＶ 时的能量微分截面及分波能量微分截面。计算结果揭示了明显的Ｒｙｄｅｒｇ 系列共振, 并使用量子亏损理论对结果进行分析和讨论, 展示了Ｒｙｄｅｒｇ 系列共振的丰富内容。     

Integrated evaluation of urban groundwater hydrogeochemistry in context of fractal behaviour of groundwater level fluctuations

The present study was carried out as part of a complex survey of urban groundwater quality and quantity in Szeged, southeast Hungary. The concentrations of 12 inorganic contaminants in 28 shallow groundwater monitoring wells were determined over a 2-year period (2010–2012). The evaluation of concentrations indicates remarkable contamination all over the city. Discriminant analysis (DA) was used to evaluate the spatial changes of groundwater quality. The groundwater levels were measured over a 14-year period (2000–2013). The fractal properties of water level fluctuations time series characterizing the groundwater system and Tisza River were investigated using rescaled range (R/S) analysis. The resulting Hurst exponents clearly showed the persistency and thus long memory effects of both the groundwater and the river flow. Comparison of the results of DA with the results of R/S analysis thus implies that the geological conditions and the changing groundwater quantities are not related to groundwater quality.

EDITOR A. Castellarin

ASSOCIATE EDITOR A. Fiori