The Nationwide Ocean Wave information network for Ports and HArbourS, NOWPHAS, has been conducted by the following organizations since 1970 for the purpose of safe marine construction works and cargo handling, port planning, the design of port and coastal facilities, and monitoring a long-term change in wave climate.
- Ports and Harbours Bureau, Ministry of Land, Infrastructure, Transport, and Tourism (MLIT)
- Tohoku, Kanto, Hokuriku, Chubu, Kinki, Chugoku, Shikoku, and Kyushu Regional Development Bureaus, MLIT
- Hokkaido Bureau, MLIT
- Okinawa General Office, Cabinet Office
- National Institute for Land, Infrastructure and Management (NILIM)
- Port and Airport Research Institute (PARI)
In the joint group, PARI is playing an important roll to:
- receive wave data from the port offices, MILT through internet and telephone lines
- calculate wave parameters and provide them on the website 'Real-time NOWPHAS'
- publish annual reports on wave statistics
The network includes the following type of wave gauges at 69 points over Japan. The wave information at 66 points is shown on the website.
- pressure gauges, measuring the variation of water pressure on the sea bed with time and converting into the water surface profile.
- ultra-sonic wave gauges, measuring the disatance from the sea bottom to the sea surface
- Doppler-type wave directional meters, combining four ultra-sonic wave sensors with a pressure sensor, estimating the directional wave spectrum
- moored GPS-mounted bouys, measuring the 3D position of the buoy every one second by using RTK-GPS technology.
The seabed gauges (pressure gauges, ultra-sonic wave gauges, and Doppler-type wave directional meters) are generally installed at a water depth of 20 to 50m within a few kilometers from the coast, while the GPS-mounted buoys are moored at a water depth of 100 to 300m and a distance of 10 to 20km.
The wave parameters such as wave height, period, and direction are calculated every 20min or 2hr. You can watch the values on the website. Unfortunately the English version is not ready. Please use the Japanese version with the .