Abstract:

Using the latest geomagnetic data of 1 334 groups, including the geomagnetic declination D, the geomagnetic inclination I and the geomagnetic total intensity F at 1 302 sites and 32 observatories in Chinese mainland, the precision and application of the enhanced magnetic model (EMM2010) have been studied. Basing on the research results, some conclusions have been drawn as follows:①The general accuracy of EMM2010 for D,I and F  in Chinese mainland, is 10.45′, 8.08′ and 112.85， respectively. Among the various regions in mainland China, the precision of EMM2010 is different. The precision in Northeast China, North China and Xinjiang is 13.07′, 8.90′ and 139.57 nT, while the precision in South China, Tibet plateau and its eastern margin is 7.07′, 6.65′ and 82.43 nT, respectively. The accuracy of the EMM2010 are caused by the factors of the limited truncation order of the EMM2010, the geomagnetic anomaly condition in various regions of China, the errors of the geomagnetic observation data and so on. ②The accuracy of EMM2010 has a distinct regional characteristic in Chinese mainland. EMM2010 accuracy is closely related to distribution, complex degree and gradient of geomagnetic anomaly condition. The higher complex degree and gradient of magnetic anomaly, the lower the accuracy of EMM2010. ③Compared with WMM2010 and IGRF11, the average accuracy of EMM2010 is increased by 50% in different magnetic elements. The main reason is that the EMM2010 includes not only the main geomagnetic field, but also the crust magnetic field. ④The analysis example of the EMM2010 used in Chinese mainland shows that it has the certain applicability, but has its limitations. The EMM2010 cannot calculate the geomagnetic field in Chinese mainland accurately. Therefore, it is necessary to study a higher accuracy geomagnetic field model to best fitting Chinese magnetic field on the basis of EMM2010 with latest survey data from different sectors for practical application.

Key words: EMM2010, WMM2010, IGRF11, Chinese mainland, accuracy