On the regime of the Earth’s polar motion based on data for the period 1962–2007

The view of the Earth’s polar motion as a completely deterministic process has been called into question in the past decades, because no long-term prediction can be made. At the same time, no fundamental restrictions currently exist in the problem of a long-term prediction of the Earth’s rotation. Determining the boundaries of predictability is related to identifying the regime of the Earth’s polar motion. IERS data for the period 1962–2007 have been used to study the regime of the Earth’s polar motion. Analysis of the plots of polhodes reveals peculiarities in the variations of the pole’s coordinates X and Y in certain intervals along the time axis. The data in the interval from 2003 to 2006 have been analyzed in greatest detail: a model for the Chandler and annual oscillations has been constructed and relations between the parameters of these oscillations have been determined; the shift of the instantaneous pole on the phase plane and the Poincare plane has been investigated. As a result, we have found features inherent in chaotic motion (intermittency) and calculated the period (32 years) of the possible repetitions of such anomalies, as confirmed by our analysis of the plots of polhodes. The intervals where the peculiarities in the motion of the Earth’s instantaneous pole manifest themselves are compared with the intervals of the inflections on the plots of variations in the length of the day (LOD).     

Geometrical Properties of Galaxy Clusters

Empirical and analytical procedures are developed to determine the morphological properties of galaxy clusters. The apparent orientations and shapes are obtainted in two dimensional space while the direction towards the cluster pole is found in three dimensional space. These properties were determined for three Abell clusters and found to be strongly related. This revised version was published online in July 2006 with corrections to the Cover Date.     

日月影响与云南未来地震趋势研究

详细分析了20世纪云南强震群体盛衰的天文背景,文中指出月亮白赤交角变化产生的交点潮[1]可能是影响地震长周期活动的一个原因。分析结果表明,20世纪以来云南的4个M≥6.7级强震活跃期有3个始发于月亮白赤交角极大年或其次年,仅第一个地震活跃期不是如此,所以总概率达80%。另外,无论太阳活动还是地震活动均存在11年的准周期,据此,作者利用20世纪云南历年最大地震的震级作了4组11年周期的外推,估计了下一个地震活跃期首发地震的时间和震级。综括上述2个天文条件,根据目前月亮白赤交角变化与太阳活动形势,我们认为云南下一个地震活跃期可能开始于2006/2007年,并可能持续活动至2015年,该期间将有较多M≥6.7级地震发生,将构成云南又一个地震重灾期。文中还对强震首发地点作了预测估计。     

全球地学断面数字化图形数据库建设

以原地质矿产部系统所完成的6条地学断面图为源数据基础,选用MAPGIS软件平台对6条地学断面图进行了数字化,根据"全球地学断面数字化指南",并参考了各地学断面的制图标准,建立了中国地学断面图形库和属性库.开发、研制了图形库管理系统.     

Quasi-periodic geomagnetic secular variation (from 1985–2005 world observatory data)

We have discovered a 2–4 year periodicity in geomagnetic secular variation (SV) from data of 110 world magnetic observatories. The periodicity in the horizontal component (H) is most prominent and appears to be globally uniform in different regions, on all continents, and in both hemispheres. The quasi-periodic short-wavelength variations show up in the vertical component (Z) as well but locally superpose on long-wavelength regional anomalies. We presume that the short-period fluctuations may be produced by instability of the eccentric dipole (ED) axis proceeding from the analysis of the SV field and optimization modeling of the dipole field with varied ED parameters.     

基于集合经验模态分解法的重力极潮提取与研究

重力极潮,即极移引起的重力变化,是地球由于惯性离心力变化导致地球形变的综合反映,其观测和研究有助于了解地球在长周期频段的响应,约束地球形变、地球内部构造和物理参数.区别于以往研究,本文采用了集合经验模态分解方法（Ensemble Empirical Mode Decomposition,EEMD）从全球5个超导重力仪台站连续重力观测资料中提取重力极潮、消除仪器漂移及极潮频段以外的大部分噪声信号,该方法所用的基函数是基于自身信号获得的;在此基础上,利用最小二乘匹配法分离极潮中的周年项和Chandler项,估算Chandler周期的极潮潮汐因子.结果表明,基于EEMD得到的极潮潮汐因子与前人基于其他消除仪器漂移方法（数学模型或小波分析）得到的结果相符合,精度相当,但由于这种方法是自适应的,因此本文结果更能反映实际物理过程.

     

板块运动规律梳理及其源动力实验计算研究

洋中脊是大洋的胚胎,从洋中脊为地堑式中央裂谷的形态特征来看,大洋是拉张应力的产物,因此必须依据大陆漂移造成海底被动扩张这一结论来分析研究板块运动的动力源问题.大陆漂移的方向是有规律的,根据世界大洋年龄图等资料进行逆推,还原不同阶段的洋陆展布状态,可以看出,白垩纪以来南半球大陆分解向北运动、北半球大陆分解向南运动,大陆在...     

具有给定超越整函数解的微分方程的唯一性

设n≥1为给定的某个自然数,pi(z)(i=1,2,3,4)是不恒为0的多项式,f(z)是1个超越整函数。如果f(z)是如下形式p1(z)[f(n)(z)]2 p2(z)f(n)(z)f(n-1)(z) p3(z)[f(n-1)(z)]2 p4(z)=0代数微分方程的解,证明如上的微分方程形式具有某种唯一性,即多项式pi(z)(i=1,2,3,4)是唯一确定的。