论文部分内容阅读
第四代地磁场综合模型CM4是迄今为止将地磁场的内源场和外源场分离得最为彻底的数学模型.利用该模型结合Taylor多项式模型,基于1960—2000年期间中国大陆地区的实测数据,计算并分析了以10a为间隔的内源场和外源场的变化情况,通过将1960—1990年的所有磁异常点归算至2000年以分析地壳磁异常场的总体分布趋势.结果显示:地磁北向分量X的内源场强度总体呈逐年减弱的趋势,从1960年到2000年共下降了约750nT,外源场强度总体呈先增强后减弱的趋势,共下降了约32nT;地磁东向分量Y的内源场强度总体呈先减弱后增强的趋势,1960—2000年期间共上升了约40nT,外源场强度总体呈先减弱后增强再减弱的趋势,共上升了约3.8nT;地磁垂直分量Z的内源场变化趋势与Y分量类似,共上升了约600nT,外源场总体呈先减弱后增强的趋势,共上升了约4.6nT.对于地壳磁异常场,X分量、Z分量、地磁总强度F和地磁水平分量H在中国大陆地区都为负异常分布,X分量和H分量的负异常强度随经度增加而减弱,Z分量和F分量则相反;Y分量和磁偏角D的分布较为类似,在中国的中西部大部分地区为正异常,强度随经度增加而减弱,磁倾角I主要以负异常为主,负异常强度随经度增加而增强.
The fourth generation geomagnetic integrated model CM4 is by far the most complete mathematical model to separate the endogenous field and the exogenous field of geomagnetic field.Based on the Taylor polynomial model and the measured data of mainland China from 1960 to 2000 , Calculated and analyzed the changes of the endogenous and exogenous fields at 10a intervals and analyzed the overall distribution trend of the anomaly fields of the crustal by calculating all the magnetic anomaly points from 1960 to 1990 to 2000. The results show that : The internal field strength of northward component X of geomagnetic field shows an overall decreasing trend from year to year. It dropped about 750nT from 1960 to 2000. The intensity of external field first increased and then decreased, decreasing by about 32nT. The intensity of the internal source field of the component Y tended to decrease first and then increased. From 1960 to 2000, the total internal field intensity increased by about 40 nT. The external field intensity decreased first and then decreased, increasing by about 3.8 nT. The trend of endogenous field of geomagnetic vertical component Z is similar to that of Y component, with a total increase of about 600nT, and the total exogenous field decreases firstly and then increases with a total increase of about 4.6nT. For the magnetic anomalies in the crust, the X component, Z Component, geomagnetic total Degree F and geomagnetic horizontal component H are all negative anomalies in the Chinese mainland. The negative anomalies of X and H components decrease with the increase of longitude, while the Z and F components are opposite. The distribution of Y and declination D is more Similarly, it is positive anomaly in most parts of central and western China, and its intensity weakens with the increase of longitude. Negative anomaly is dominant in the inclination I and negative anomaly is enhanced with the increase of longitude.