The Study of Magnetic Field Models for Philippines
详细信息
- 责任者：Di Chuanzhi (Geophysical Institute of China Earthquake Administration ; Beijing 100081 ; China) ; Gu Zuowen
- 刊名：Chinese Journal of Geophysics
- 出版年：2011
- 卷期：54(8)
- 关键词：地磁场 ; geomagnetic field ; 菲律宾 ; Philippines
- 页码：p.2085-2092
- 图表：6 illus., 2 tables, 18 refs.
- 分类号：0400
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
According to the magnetic field data at 74 survey sites measured in the Philippines during 2001-2007, and using two methods of spherical cap harmonic and Taylor polynomial, we established magnetic field model on 2005.0 epoch for Philippines and the surrounding regions and got the distribution of the seven components of X, Y, Z, D, I, H, F. The distribution is similar in the two models, the difference is in the relief of inflection point and contour smoothness. At about 8°N, X, H, F have turning point and they are higher in west than in east. D, Y zero line extends approximately along latitude 8° N, the northern side of the line is negative and the southern part is positive, while the distribution of the contours is along the longitude direction,with minor variation along latitude direction. The distribution of Z and I is more regular, the zero-line is along 7. 5°N, and the value is positive in northern region and negative in southern regions. The distribution patterns of the difference between the two models with the IGRF are very different, the value of spherical harmonic model minus IGRF model revealed a feature of alternative positive and negative anomalies, and the maximum positive and negative anomaly value of each component is in low latitudes. The anomaly distribution of Taylor minus IGRF is smoother.