Spherical cap harmonic analysis of regional magnetic anomalies based on CHAMP satellite data
Feng Yan1,2, Jiang Yong1, Jiang Yi1, Liu Bao-Jia1, Jiang Jin1, Liu Zhong-Wei1, Ye Mei-Chen1, Wang Hong-Shen1, and Li Xiu-Ming1
1. The College of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing 210044, China.
2. Sate Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100080, China.
Abstract：
We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over mainland China. We assumed satellite points on the same surface (307.69 km) and constructed a spherical cap harmonic model of the satellite magnetic anomalies for elements X, Y, Z, and F over Chinese mainland for 2010.0 (SCH2010) based on selected 498 points. We removed the external field by using the CM4 model. The pole of the spherical cap is 36N° and 104°E, and its half-angle is 30°. After checking and comparing the root mean square (RMS) error of ?X, ?Y, and ?Z and X, Y, and Z, we established the truncation level at Kmax = 9. The results suggest that the created China Geomagnetic Referenced Field at the satellite level (CGRF2010) is consistent with the CM4 model. We compared the SCH2010 with other models and found that the intensities and distributions are consistent. In view of the variation of F at different altitudes, the SCH2010 model results obey the basics of the geomagnetic field. Moreover, the change rate of X, Y, and Z for SCH2010 and CM4 are consistent. The proposed model can successfully reproduce the geomagnetic data, as other data-fitting models, but the inherent sources of error have to be considered as well.
. Spherical cap harmonic analysis of regional magnetic anomalies based on CHAMP satellite data[J]. APPLIED GEOPHYSICS, 2016, 13(3): 561-569.
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