试论磁场总量异常△T近似为调和场的误差

A PRELIMINARY DISCUSSION ON THE ERROR OF TOTAL MAGNETIC FIELD ANOMALY ΔT APPROXIMATE TO HARMONIC FIELD

对磁场总量异常△T近似为调和场的误差进行了讨论,给出了△T近似为调和场的误差值估算式。同时指出△T近似为调和场的误差与磁异常强度的模量Ta、正常地磁场强度T0的方向变化值ψ呈正相关,与正常地磁场强度的模量T0呈负相关。当磁异常强度Ta与正常地磁场强度T0的夹角θ值接近π/2或3π/2时,误差为最大值。根据工区磁场特征,利用误差估算式估算△T近拟为调和场的误差值,合理地确定出磁测资料解释推断精度和磁测精度,避免了磁测资料的"过度"解释推断和磁测精度的"虚高",这在高精度磁测工作中有较大实用价值。

The error and estimation formula of approximating total magnetic field anomaly ΔT as harmonic field is discussed in this paper.It shows that the error is positively correlated with modulus T_a of magnetic anomaly strength as well as the direction change value ψ of normal magnetic field strength T_0.In contrast,the error is negatively correlated with the modulus T_0 of normal magnetic field strength.Tests find that the error reaches the maximum when the angle θ between magnetic anomaly strength T_a and normal magnetic field strength T_0 closes to π/2 or 3π/2.According to characteristics of the work area magnetic field,the estimation of the error of approximating total magnetic field anomaly ΔT considering as harmonic field using the error estimation formula,can reasonably determine the precision of magnetic survey data interpretation and magnetic survey,and it avoids 'excessive' data interpretation and 'virtual high' precision of magnetic survey.It has great practical value in the high-precision magnetic survey.