XU Xing,
ZHAO Xu-Dong,
WANG Gong-Xiang et al
.2017.Analysis of data from the deep-sea geomagnetic observation buoy in the southwest subbasin of the South China Sea.Chinese Journal Of Geophysics,60(3): 1179-1188,doi: 10.6038/cjg20170328
Analysis of data from the deep-sea geomagnetic observation buoy in the southwest subbasin of the South China Sea
XU Xing1, ZHAO Xu-Dong2, WANG Gong-Xiang1, LIAO Kai-Xun1, LIU Yu-Qiang3, YANG Zhuo-Hao1
1. MLR Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, Guangzhou 510075, China; 2. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China; 3. South China Sea Branch, State Oceanic Administration, Guangzhou 510310, China
Abstract：Sea-surface and sea-bottom measurements at the same location can yield different results of the geomagnetic field due to the disturbance of seawater cutting geomagnetic lines and relevant electromagnetic induction. Although previous studies more or less document such differences, little measurements can characterize their space-temporal variations. This paper presents observations from a recent experiment in the southwest subbasin of the South China Sea by using a 4-km-long deep-sea geomagnetic buoy. The data display a complete measurement of the geomagnetic field in the seawater column at all depths, allowing us to analyze its vertically-varying characteristics in the total intensity and phase. Compared with three nearby observatories with a Sq model, observed diurnal variations show similarity in magnetic quiet periods. However, during the magnetic disturbance period, notable discrepancies exist, probably caused by the effects of diverse sub-seafloor electric media on induced current. This study is significant in evidencing the changes of the geomagnetic field with both time and depth in an abyssal basin, as well as in advising for the design of the diurnal variation observatory in marine magnetic surveys.
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