Application of geomagnetic field model to marine magnetic data processing

The correction of geomagnetic diurnal variation is an important step for marine magnetic data processing. In this paper, the geomagnetic diurnal variation data of a survey area in the western Pacific Ocean was calculated using the integrated model and the IGRF model, and the results were analyzed by comparing with the observation data from the same marine geomagnetic diurnal variation stations. Both of the two kinds of data were used to process the magnetic data for the 15 survey lines in the survey area, and error analyses are made for all the survey lines and their 56 intersections. The results suggest that: (1) When the calculated data is used for the processing of marine magnetic survey data, the accuracy of the intersection points basically meets the requirements of the specifications for marine geological survey before the adjustment, and completely meets the requirements of the specifications for marine geological survey after the adjustment, but the accuracy of the calculated data is lower than the measured data. (2) The calculated diurnal variation curve had higher fitting degree with the measured in magnetostatic condition, while the amplitude difference between them is larger in the case of magnetic disturbance, and correlation coefficient decreased with the enhancement of magnetic disturbance. The model calculated data of K＞4 must be used with caution or never be used.