全球海表温度变化与中国夏季降水异常分布

用奇异值分解分离出全球范围及北太平洋海域海表温度与中国夏季降水相关的空间分布结构．经分析得到：当太平洋、大西洋和印度洋海温呈某种特定配置时,特别是当北太平洋的海温呈典型厄尔尼诺型态或暖池附近海温发生异常变化时,对中国夏季雨带位置的变化起一定作用．但就中国大范围而言,海温对夏季降水所起的作用没有达到０．０５显著性水平．海温的变化及特定配置与西北地区夏季降水有较显著的统计关系．     

赤道太平洋区域风应力与海表温度年际异常的奇异值分解

用向量场奇异值分解方法分析了赤道太平洋区域风应力场与海表温度场年际异常的相关联系。结果表明,最主要的一对奇异向量与ENSO循环关系密切,其主要特征为赤道中、东太平洋风应力向赤道的异常辐合（辐散）与该区的SST异常升高（降低）准同步变化。对70和80年代的4次 El Ni?o事件中标准化风应力异常场的分析表明,它们均表现出赤道中、东太平洋的辐合。这一结果可能比用信风张弛描述ENSO循环中的环流异常更合理和更具代表性。     

奇异摄动问题UWMCB法的非古典估计

用ＵＷＭＣＢ法对一维的对流扩散问题进行分析，指出：当以对流为主时，可得到非古典的局部收敛估计及一致收敛估计，证实ＵＷＭＣＢ法是一种精度较高的数值解方法．     

一类非线性奇异边值问题的解的存在性

本文研究了如下的高阶奇异边值问题解的存在性ｙ（ｎ）＋ｆ（ｔ，ｙ，ｙ＇，．．．，ｙ（ｎ－２））＝０，ｎ≥２，０＜ｔ＜１，ｙ（ｉ）（０）＝０，０≤ｉ≤＜ｎ－２，ｙ（ｎ－１）（１）＝０其中，ｆ（ｔ，ｙ１，．．．，ｙｍ－１）在ｙｉ＝０处有奇性，ｉ＝１，．．．，ｎ－１。我们给出了该问题解存在的一个新的充分条件     

单站地基GPS天顶延迟反演大气剖面研究

基于一定的大气折射率剖面模型和搜索方法,可以由GPS天顶延迟反演大气折射率剖面。利用上海气象站的探空数据和上海IGS站的GPS数据,对基于单站地基GPS天顶延迟的大气折射率剖面反演方法进行了验证。结果表明,根据目前处理得到的天顶延迟,反演剖面与实际剖面吻合较好。     

Signals of short‐term climatic periodicities detected in the groundwater of North China Plain

Growing demand on groundwater resources and the semi‐arid climate in the North China Plain (NCP) highlight the need for improved understanding of connections between regional climate change and groundwater recharge. Hydrologic time series of precipitation and groundwater levels were analyzed in three representative geographical zones throughout the NCP for the period of 1960–2008 using trend analysis and spectral analysis methods. A significant change point around 1975 is followed by a long‐term decline trend in precipitation time series, which coincides with the Pacific Decadal Oscillation positive phase. However, the magnitudes of groundwater level variability due to heavy pumping overwhelm the low‐frequency signal of groundwater levels. Nonlinear trends that related to long‐term climatic variability and anthropogenic activities are removed by using the Singular Spectrum Analysis method. Spectral analyses of the detrended residuals demonstrate significant short‐term oscillations at the frequencies of 2–7 years, which have strong correlations with the El Niño–Southern Oscillation modes. This study contributes to improved understanding of dynamic relationship between groundwater and climate variability modes in the NCP and demonstrates the importance of reliable detrending methods for groundwater levels that are affected greatly by pumping. Copyright © 2015 John Wiley & Sons, Ltd.     

Singular value decomposition of the compliance response matrix for the triaxial stress condition

Performance-based design demands accurate prediction of soil deformation under a working load condition. The nonlinear stress–strain behavior needs to be analyzed quantitatively to advance the understanding of complex soil behavior in the pre-failure condition. The singular value decomposition technique is introduced to quantitatively analyze the compliance matrix representing the strain response envelope (SRE). The rotation of the ellipse of the SRE relates to the anisotropic response of the soil deformation. The off-centered SRE provides evidence of the kinematic hardening plasticity. Quantitative data on the movement of SREs provide us with crucial information to investigate the effect of stress history and the evolution of stiffness anisotropy in soil deformation.     

http://www.sciencedirect.com/science/article/pii/S1674987110000368

In this paper,we show that geo-anomalies can be delineated for mineral deposit prediction according to singularity theories developed to characterize nonlinear mineralization processes.Associating singularity and geo-anomalies makes it possible to quantitatively study geo-anomalies with modern nonlinear theories and methods.This paper introduces a newly developed singularity analysis of nonlinear mineralization processes and nonlinear methods for characterizing and mapping geo-anomalies for mineral depos...     

A BOOTSTRAP RESAMPLING SCHEME FOR USING THE CANONICAL CORRELATION TECHNIQUE IN RANK ESTIMATION

Rank estimation by canonical correlation analysis in multivariate statistics has been proposed as analternative approach for estimating the number of components in a multicomponent mixture.Amethodological turning point of this new approach is that it focuses on the difference in structure ratherthan in magnitude in characterizing the difference between the signal and the noise.This structuraldifference is quantified through the analysis of canonical correlation,which is a well-established datareduction technique in multivariate statistics.Unfortunately,there is a price to be paid for having thisstructural difference:at least two replicate data matrices are needed to carry out the analysis.In this paper we continue to explore the potential and to extend the scope of the canonical correlationtechnique.In particular,we propose a bootstrap resampling method which makes it possible to performthe canonical correlation analysis on a single data matrix.Since a robust estimator is introduced to makeinference about the rank,the procedure may be applied to a wide range of data without any restrictionon the noise distribution.Results from real as well as simulated mixture samples indicate that when usedin conjunction with this resampling method,canonical correlation analysis of a single data matrix isequally efficient as of replicate data matrices.     

STATISTICAL F-TESTS FOR ABSTRACT FACTOR ANALYSIS AND TARGET TESTING

Fisher variance ratio tests are developed for determining(1)the number of statistically significantabstract factors responsible for a data matrix and(2)the significance of target vectors projected into theabstract factor space.F-tests,developed from the viewpoint of vector distributions,are applied tovarious data sets taken from the chemical literature.