New System to Measure Tides Using Laser Beams Eyed For 2025; NEC Draws Lessons from Noto Peninsula Earthquake

The Yomiuri Shimbun

6:00 JST, July 17, 2024

NEC Corp. has developed a new system to measure tide levels with high accuracy using laser beams and buoys on the ocean’s surface. The company aims to put the system into practical use in fiscal 2025, with expectations it will be used by the central and local governments.

During the Noto Peninsula Earthquake in January, the ground shifted so greatly that the seabed rose above the surface of the ocean, making measurement impossible for an extended period. With that experience in mind, NEC started working on its new system.

Conventional methods to measure tide levels use radio waves. The waves are directed towards the surface of the sea from above, and the time taken for them to be reflected back is calculated. Measuring tide levels with this method requires equipment to be fixed to the coast. Therefore, when ground motion shifts the equipment, accurately measuring the tide becomes difficult. The recovery process takes a long time too.

The new system, however, emits infrared laser beams from a device on a distant piece of land to measure the distance between buoys floating on the sea’s surface tens or hundreds of meters away and nearby dikes and structures. The system measures the tide level by comparing changes in the positions of the buoys and the structures. The system is less susceptible to the effects of ground motion and is expected to be more accurate.