摘要
本文提出一种能净化处理流动地磁观测所得的总强度数据的多道约束维纳滤波法。它只要求对测网中各测点进行一次总强度F、磁偏角D和磁倾角I的绝对测量,使其满足所需的约束条件,便能利用附近地磁台同时段的三分量数据精确地拟合得出各测点在各观测期间的三分量值。这样,就可算出相邻两点间总强度差矢量的大小和方向,排除地磁内、外源场的干扰。进而再利用该台的三分量扰动场数据,通过同样的滤波运算,可先后获得相邻两点间跟构造应力作用有关的感应场与剩余场。以台距为144～455公里的北京、静海、昌黎和红山四个地磁台的144个分量数据进行检验,结果表明:(1)各分量的拟合值与真值之差的标准差分别为σ_X=1.22～2.65nT,σ_Y=1.16～3.97nT,σ_Z=1.18～2.32nT,σ_F=1.18～2.34nT;(2)拟合值的均值与真值的均值之差则很小。X_f-X_o和Z_f-Z_o都是零,Y_f-Y_o=-0.2～-0.3nT,F_f-F_o=0.2～0.3nT;(3)所算出的总强度差矢量之均值的大小和方向与真值的几乎完全相等;(4)感应场不足1nT,远远小于剩余场。
The multichannel constrained Wiener filtering used in the purificationprocessing of data of the total magnetic strength registered in the mobilegeomagnetic observations is proposed in this paper. This method demands nolyone run of absolute measurement at respective survey sites of the total magneticstrength F, magnetic declination D and magnetic inclination I to satisfy theconditions of restraints, then it would be able to obtain accurate values forthe 3 components of respective sites during the observation by fitting the 3-component data of the neighboring observatories collected during the same observationperiod. By so doing, it would be possible to calculate the size and directionof the vectors of the total strength difference for any 2 neighboring sites, toexclude the noise factors caused by the inner and outer geomagnetic fields.The 3-component data of the perturbation field of the observatory are further usedto run the same filtering calculations, and it is possible to obtain the inducedand residual fields between 2 neighboring sites which are related with thetectonic stress. This method is tested using 144 3-component data respectivelyregistered at Beijing, Jinghai, Changli and Hongshan geomagnetic observatorieswhich have station-separations of 144-455 kilometers. The result of the testcalculation shows the following:1) The standard deviations between eachcomponent's fitted and true values are respectively σX = 1.22-2.65 nT; σY =1.16-3.97 nT;σZ = 1.18-2.32 nT and σF=1.18-2.34 nT. 2) The deviationsbetween the mean values respectively of the fitted and true values is verysmall. Xf-X-o=0, Zf-Zo= 0, Yf-Yo = 0.2-0.3 nT and Ff-Fo =0.2-0.3nT. 3) The sizes and directions respectively of the mean and true values of thevectors of the calculated total strength differences nearly equal with one another. 4) The induced field is less than 1 nT, and is much smaller than the residual field.
出处
《地震研究》
CSCD
北大核心
1991年第4期367-388,共22页
Journal of Seismological Research
关键词
地磁
观测
构造磁
维纳滤波
净化
Tectonomagnetism
Induced field
Residual field
Purification processing
