| Popis: |
The natural electric field at the depth of 0~1500 m in high seas of South China Sea is obtained by using a new type of measuring device. The electric field data in the frequency range of 0.01~0.5 Hz and 0.5~30 Hz are analyzed respectively. The results show that the induced electric field generated by the surface wave (about 0.14 Hz in the experiment) is obvious at the depth of 50 m but can be ignored at the depth greater than 100 m. When the depth increases from 50 m to 1500 m, the peak value of the natural electric field gradually decreases. At the depth of 1000 m, the peak value is 0.04~0.08 uV/m for electric field in 0.01~0.5 Hz, and 0.07~0.1 uV/m for electric field in 0.5~30 Hz. At last, the natural electric field in coastal waters near Sanya City where the water depth is 15 m is measured by means of a sinking device. The results show that, the peak value is about 2~4 uV/m for electric field in 0.01~0.5 Hz and 2 uV/m for electric field in 0.5~30 Hz. By comparing the natural electric field between high seas and coastal waters, we find the latter has a larger peak value than the former at nearly the same water depth. In addition, line spectrum noise often occurs in coastal waters while little line spectrum noise in high seas when the water depth is more than 50 m. |
