第23周太阳活动峰年北京天文台太阳射电观测

An introduction to the instrumonts to be used for solar radio observations in Beijing in Solar Cycle 23 is made in this paper. They are 10cm solar radio telescope which has been used for a long time,and 1.0～2.0GHz,2.6～3.8GHz and 5.2～7.6GHz spectrometers. The former two spectrometers has passed a test,showing high guality,and the 5.2～7.6GHz one will be in operation from 1999. It is believed that highl gualified data should be obtained in the next solar cycle.     

吉林大阳岔上寒武统凤山组—下奥陶统冶里组层序地层和化学地层研究

根据岩相序列、沉积、成岩作用特征,将吉林省大阳岔地区晚寒武世凤山期至早奥陶世冶里期层序地层分为６个三级层序,代表了６个三级海侵—海退旋回;与之相应,该时期碳酸盐岩δ１３Ｃ值变化曲线出现５个低谷,其中凤山期至冶里早期泥晶灰岩δ１３Ｃ值出现４次幅度较大的上升、下降飘移,而冶里中、晚期泥晶灰岩的δ１３Ｃ值是在负值范围内波动。δ１３Ｃ值低谷与层序界面和海退事件基本拟合。牙形类Ｃ．ｉｎｔｅｒｍｅｄｉｕｓ带下部海绿石质凝缩段是寒武纪末—奥陶纪初期最大海泛事件沉积,也是寒武纪与奥陶纪之交等时性的年代地层对比标志。     

On solution of the inverse problem for confined aquifer flow via maximum likelihood

Joint estimation of transmissivity (T) and storativity (S) in a confined aquifer is done via maximum likelihood (ML). The differential equation of groundwater flow is discretized by the finite-element method, leading to equation _t+x _t=u _t. Elements of matrices and , as well as estimated covariance matrix of noise termu _t, are functions of T and S. By minimizing the negative loglikelihood function corresponding to discretized groundwater flow equation with respect to T and S, ML estimators are obtained. The ML approach is found to yield accurate estimates of T and S (within 9 and 10% of their actual values, respectively) and showed quadratic convergence in Newton's search technique. Prediction of aquifer response, using ML estimators, results in estimated piezometric heads accurate to ±0.5 m from their actual, exact values. Statistical properties of ML estimators are derived and some basic results for statistical inference are given.     

A preliminary study on sediment flux in the Changjiang Delta during the postglacial period

During the last 7000 years since the Changjiang Delta was formed, how much sediment brought by the Changjiang River remained in the modern Changjiang Delta? And how much sediment was delivered into the sea and adjacent coasts? These are very important que…     

Appraisal of Seismic Hazard Parameters for the Seismic Regions of the East Circum-Pacific Belt Inferred from a Bayesian Approach

The assessment of seismic hazard parameters is important in the seismically active regions. A straightforward approach is considered for the statistical estimation of the maximum values of earthquake hazard parameters. The Bayesian estimator is suggested and emphasis is given to the evaluation of the maximum possible M_max (regional) magnitude in a future time interval T. This approach allows the uncertainty of earthquake magnitude to be accounted for. Seismic hazard parameters like the -value which is the slope of the magnitude-frequency law (where, b = log_e) and the intensity (rate) of seismic activity and their uncertainties are also estimated. The quantiles of functions of distributions of true and apparent magnitude on a given time interval [0, T] are evaluated, as well. Two main assumptions are adopted for the method:(1) earthquake occurrence is Poissonian and(2) the magnitude-frequency law is of Gutenberg-Richter type with a cutoff maximum value of magnitude. It is needless to say the seismic catalog used must have a large number of events. This requirement leads to the estimation of the parameters referred to some of the most seismically active regions of the world, e.g., Chile, Peru-Equador-South Colombia,Central America and Mexico, which belong to the east part of the circum-Pacific belt.     

Modelling peak accelerations from earthquakes

This paper deals with the prediction of peak horizontal accelerations with emphasis on seismic risk and insurance concerns. Non‐linear mixed effects models are used to analyse well‐known earthquake data and the consequences of mis‐specifying assumptions on the error term are quantified. A robust fit of the usual model, using recently developed robust weighted maximum likelihood estimators, is presented. Outlying data are automatically identified and subsequently investigated. A more appropriate model accounting for the extreme value nature of the responses, is also developed and implemented. The implication on acceleration predictions is demonstrated. Copyright © 2006 John Wiley & Sons, Ltd.     

基于小波变换模极大值的滑坡监测数据处理方法及其实现

首先给出小波变换模极大值法用于滑坡体位移监测曲线去噪的处理方法,并对该方法在MATLAB中的实现进行了研究和探讨,给出了实现的算法步骤以及相应的MATLAB程序代码。利用实际数据资料,在MATLAB下进行滑坡体位移监测曲线去噪试验,取得了较理想的效果。实验结果表明,将小波变换模极大值法用于滑坡体数据处理,不但可以有效地消除噪声,而且还可以保持信号的阶跃或突变点的位置不变。     

基于TM影像的南京市土地利用遥感动态监测

基于南京市1988年和1998年两期TM影像，首先用辐射水准归一化法将1998年影像校正到1988年影像的辐射水平上，再经过几何校正、训练区纯化等预处理，对两期影像分别用最大似然法进行分类，然后在Arc／Info的GRID模块中编写AML语言，对得到的两期土地利用分类图进行叠置运算，提取出土地利用动态变化信息。分析结果表明，10a间南京市耕地面积大量减少，林地面积有所增加。     

江苏省最大日降水量时空分布特征及其统计拟合

本文根据江苏省内60个观测站1961~2000年的逐日降水资料,分析省域日最大降水的空间分布特征及年度变化,建立了省内日最大降水的概率分布模式,从而推算分析出现大降水的概率。研究结果表明皮尔逊Ⅲ型概率分布模式能够较好的拟合大暴雨的分布特征。     

查表法设计华北地区最大震级时间序列模糊预测系统

本文介绍了查表法设计模糊系统(FSLE)的方法与原理,然后基于该方法建立了华北地区及主要地震带最大震级时间序列的预测模型,并进行了预测内符检验。分析认为,该方法的建模与预测精度较高,模型外推泛化能力较强,原理简单直观,计算结果稳健。因此,FSLE方法可作为地震趋势建模与预测分析工作中的一种有效工具。