不同方式地磁观测数据对磁测精度的影响分析

地磁日变改正数据的合理选取直接关系到海洋磁测的成果精度。通过在南海南部海域布放的一个4 000m长的地磁观测潜标及同步开展的磁力测量,并在收集周边陆域地磁台站数据的基础上,对水体中获得的地磁日变观测数据和水面磁测数据进行综合分析和研究,得到几点认识:(1)浅水海域获得的日变观测数据用于海洋磁测数据处理时,其测量准确度比深水海域的好,且与陆域地磁台站数据曲线的一致性要高;(2)船磁校正曲线是否对称与地磁日变观测数据的合理选取密切相关;(3)在远海区磁测时,为确保详尽记录局部磁扰,建议海底地磁日变观测站应布放于靠近工区、水深较浅的水体之中。

Analysis of Effects Made by Using Different Geomagnetic Observation Data upon Magnetic Measurement Precision

The reasonable selection of diurnal magnetic correction data is directly related to marine magnetic survey data precision.This paper describes a 4000m long geomagnetic observation submerged buoy which is put in the southern South China Sea and the simultaneously surface magnetic survey.Based on the analysis and study of the marine diurnal variation data,surface magnetic data and land magnetic observatory data nearby,following conclusions are obtained.Firstly,when applying diurnal magnetic data to process marine survey data,the accuracy of shallow water data is better than that of deep water.What is more,the shallow water data has higher consistence with land magnetic observatory data than that of deep water.Secondly,whether the ship magnetism heading error correction curve is symmetrical or not is highly related to the reasonable selection of diurnal magnetic data.Lastly,for the sake of fully recording of local magnetic disturbance when executing marine magnetic survey in open sea,the marine magnetic diurnal observation device is recommended to deploy in shallow waters as close to working area as possible.