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磁张量梯度能提供地磁场矢量在三维空间的变化率信息,对地质构造研究、资源勘查、地磁导航等具有重要意义。但目前工程技术条件下磁张量梯度测量在却很难实现,为此本文提出一种使用航磁三轴梯度资料计算磁张量梯度的方法,满足无法直接测量全张量梯度情况下对资料的需求。区别于单轴航磁梯度转换全张量梯度的方式,该法使用航磁三轴梯度数据进行转换,能充分利用磁异常模量在三维空间上的变化信息,获得自洽的磁张量梯度。理论模型计算表明该转换方法获得的全张量梯度数据具有较高的数值精度,能够满足实际资料处理的要求。我们选取河北保定地区实测的航磁三轴梯度资料进行全张量梯度资料转换,实际资料处理结果表明,联合三轴梯度进行全张量梯度转换能够有效利用磁异常在全空间的变化信息,压制三轴梯度资料中部分相互独立的噪声,从而提升转换后全张量梯度资料的品质,转换得到的航磁全张量梯度可作为一种地球物理场资料供地质解释使用。
The magnetic tensor gradient can provide the rate of change of the geomagnetic field vector in three-dimensional space and is of great significance to the study of geological structure, resource exploration and geomagnetic navigation. However, under current engineering and technical conditions, it is very difficult to measure the magnetic tensor gradient. Therefore, a method to calculate the magnetic tensor gradient using aeromagnetic triaxial gradient data is proposed in this paper. The method can not meet the requirement of directly measuring the total tensor gradient. The demand. Differing from the method of full-tensor gradient transformation of uniaxial magnetic gradient, this method uses the magnetic three-axis gradient data to transform, which can make full use of the change information of magnetic anomaly modulus in three-dimensional space to obtain self-consistent magnetic tensor gradient . The theoretical model calculation shows that the total tensor gradient data obtained by the conversion method has high numerical precision and can meet the requirements of actual data processing. We select the measured data of aeromagnetic triaxial gradient in Baoding area, Hebei Province, to conduct full-tensor gradient data conversion. The actual data processing results show that the combination of the three-axis gradient full tensor gradient transformation can effectively utilize the information of magnetic anomalies in the whole space and suppress The three-axis gradient data are partially independent of each other to enhance the quality of the converted total tensor gradient data. The converted total magnetic anisotropy gradient can be used as a geophysical data for geological interpretation.