Analysis of the effect of differences in the base value of geomagnetic daily variation on marine magnetometry

Geomagnetic daily variation is the main source of error affecting marine magnetic measurements. In this paper, the influence of the geomagnetic daily variation base value on marine magnetic measurements is theoretically analysed in relation to the characteristics of geomagnetic daily variation, and its influence on the calculation of the cross-point difference of the magnetic survey results is discussed and calculated and analysed by means of actual data. The conclusions show that when a survey area is completed by more than one cruise, the different base values of geomagnetic daily variation selected by different cruises will have an impact on the cross-point difference, thus affecting the accuracy of the marine magnetic survey results. With reasonable adjustments, the accuracy of data processing can be improved and the quality of marine magnetic measurements can be improved.