抄録
This paper introduces characteristics of waves and tides as physical phenomena, and coastal observation system of waves and tides in Japan. Although waves and tides are both periodical sea-surface motion, as their periods are different, different methods are applied for their observation.
NOWPHAS (Nationwide Ocean Wave information network for Ports and HArbourS), Japanese coastal wave observation system, are mainly consist of the sea-bed installed type wave gauges. Due to the development of the Doppler-type Wave Directional Meter (DWDM) and continuous tsunami and infra-gravity wave observation and analysis system, and due to the establishment of the Coastal Wave Center (Coastal Wave Information Department of the Coastal Development Institute of Technology), NOWPAHS made remarkable changes during the last decade.
Tidal observation has been conducted mainly by using the Float-type Tide Gauges all over the Japanese coasts with installation of tide wells. Recently new simple tide observation methods without necessity of tide well construction are studied and developed such as the On-air-type acoustic tide gauge.
