What is a tsunami warning buoy? Do you know what it does?

1. Introduction to Tsunami Warning Buoys

Tsunami disasters are important marine disasters, causing more than 250,000 deaths and disappearances worldwide in the 21st century alone. Tsunami warning buoys are internationally recognized as an effective means of early detection and monitoring of tsunami waves, and are the core equipment of the new generation of tsunami warning systems. Tsunami warning buoys use high-precision pressure sensors deployed on the seabed to monitor sea level changes, automatically identify tsunami waves or abnormal fluctuations and report them in real time. They have the characteristics of sensitive response, accurate data, and strong real-time performance.

The tsunami warning buoy consists of two parts. The tsunami detector located on the seabed can collect, process, judge and report the seabed pressure data; the anchored buoy located on the sea surface receives the data sent by the seabed tsunami detector, and transmits it to the ground control center via satellite after editing and processing. Similarly, the ground control center can also transmit instructions to the sea surface buoy via satellite, and then forward them to the tsunami detector in real time using an acoustic communication machine.

Figure 1 Tsunami warning buoy system

2. Breakthrough in key core technologies and achieve international leadership

my country officially became a member of the International Tsunami Coordination Group in 1983, and since then the Ministry of Natural Resources (formerly the State Oceanic Administration) has started my country's tsunami warning business. With the support of national scientific research projects such as the Ocean Public Welfare Project, the National Ocean Technology Center took the lead in developing a tsunami warning buoy system, filling the domestic technology gap and playing an important role in my country's tsunami warning system.

Through years of research and development of tsunami warning buoys, we have mastered tsunami wave recognition algorithms with independent intellectual property rights, made breakthroughs in key core technologies such as real-time and reliable transmission of hydroacoustic data and satellite data, shortened tsunami warning time, and provided important technical support for the commercial operation of tsunami warning. The technical achievements of tsunami warning buoys won the second prize of the 2021 Marine Science and Technology Award, and the technical performance has reached the international advanced level.

The maximum working depth of the tsunami warning buoy can reach 6000m. It uses high-precision pressure sensors and digital filtering technology to achieve a sea level height measurement resolution of 1mm. It is embedded with a tsunami wave detection and recognition algorithm based on Newton interpolation polynomials, which can automatically identify tsunami waves with an amplitude of more than 3cm. The monitoring data is transmitted to the ground in real time through hydroacoustic communication and satellite communication, reporting tsunami wave amplitude and tsunami wave time data. Combined with the tsunami wave propagation pattern database, the time series data of one or more tsunami buoys are inverted to predict the tsunami threat in the entire ocean and provide input parameters for the fixed-point inundation forecast model of coastal communities that may be affected. Direct and real-time monitoring of tsunami energy in the deep sea outside the tsunami source can improve the timeliness and accuracy of tsunami warnings. Continuous ocean monitoring can greatly improve the accuracy and timeliness of tsunami forecasts and help emergency management departments make evacuation or disaster relief decisions.

The tsunami warning buoy has been successfully applied in the South China Sea. Four deep-sea tests were conducted in 2015-2016, including a 3,871-meter test and a 108-day application demonstration test. It has successfully achieved high-precision sea level height measurement, data processing and calculation, tsunami wave judgment and identification, seamless switching of multiple working modes, and real-time and regular data reporting functions, achieving good demonstration operation results. In the test area, the tsunami warning buoy can monitor the tsunami caused by the three faults in the northern part of the Manila Trench within 15-45 minutes, providing Hainan Island with a warning time of about 2 hours, and providing Guangdong, Fujian, Zhejiang and other mainland coastal areas with a warning time of 3-5 hours, effectively improving my country's tsunami monitoring and warning service capabilities, and providing strong guarantees for the development of the marine economy in coastal provinces and cities.

Figure 2 Tsunami warning buoys deployed in the South China Sea

Figure 3 Deployment of underwater subsystem of tsunami warning buoy