EMM2010模型在中国大陆的精度评估及其适用性

基于我国大陆最新观测所得的1 302个地磁测点和32个地磁台站磁偏角D、磁倾角I、总强度F的1 334组准确数据，并结合地壳磁异常能谱变化特征，对增强地磁模型(EMM2010)在我国大陆的精度及其适用性进行了定量分析。结果表明：EMM2010模型(D、I、F)在我国大陆的总体精度分别为10.45′、8.08′、112.85 nT  ；东北、华北与新疆地区模型的精度为13.07′、8.90′、130.89 nT ；华南、青藏高原及其东缘地区模型的精度为7.07′、6.65′、81.84 nT；其精度是受模型有限的截断阶数、各区域的磁异常状况和磁测数据的误差等因素共同影响的。EMM2010模型的精度在我国大陆表现出显著的地域分布特征，与磁异常的分布形态及其复杂程度、梯度密切相关，异常越突出，形态越复杂，模型的精度越低。与世界地磁模型(WMM2010)、第11代国际参考地磁场(IGRF11)相比，EMM2010模型在我国大陆的总体精度平均提高了50%，主要原因是模型不仅包含了地球主磁场，同时还包含了地壳磁场。EMM2010模型应用于我国大陆的实例及精度分析表明，模型具有一定的适用性，但有其局限性，不能准确反映出我国大陆的地磁场信息，鉴于模型的精度，建议在EMM2010模型基础上，结合我国最新的各部门的高精度磁测数据，构建我国高精度的地磁场模型。

Accuracy and Application of EMM2010 in Chinese Mainland

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.