Calculates the electric specific conductance under the seabed by measuring the underwater electric field which accompanies the ship the manner

摘要

PROBLEM TO BE SOLVED: To calculate electric conductivity under the bottom of the sea by measuring the underwater electric field caused by the underwater current flowing across the metal products of the bottom of a sailing ship by the electric field sensor on the bottom of the sea and setting the surface of the sea and the bottom of the sea to boundaries to calculate the electric conductivity from the measured value. ;SOLUTION: Two electrodes are provided on the bottom of a ship 4 straightly advancing on the sea in a definite direction and the waveform of the underwater electric field generated by the underwater current flowing across two electrodes is measured with respect to its horizontal and vertical components by the three-axis electric field sensor 1 provided on the bottom 6 of the sea to be transmitted to a processor 3 by an underwater cable 2. At the same time, the position of the ship 4 is measured by an optical method and the electric conductivity of seawater is measured by a conductivity meter. The processor 3 computes the electric conductivity under the bottom 6 of the sea from the measured value regarding the surface 5 of the sea and bottom 6 of the sea as boundaries and also regarding the mirror image moments to the surface 5 of the sea and the bottom 6 of the sea of the moment of the ship 4 as the electric field formed at a measuring point. By this constitution, work in the sea may be accomplished by only the laying work of the underwater cable 2 and the electric conductivity under the bottom 6 of the sea can be easily measured.;COPYRIGHT: (C)1998,JPO