What Is Significant Wave Height?

Wave height refers to the vertical distance between the adjacent peaks and troughs. Usually expressed as H, as shown in the figure. In engineering, forecasting and other applications, wave height is usually defined based on the upper span zero. For the wave surface records of fixed-point observations, the wave height is the height difference between the significant wave peak on one side of the road zero and the significant wave valley on the other side.

Wave height is one of the wave elements, which refers to the height difference between the adjacent peaks and troughs. In engineering, forecasting and other applications, wave height is usually defined based on the upper span zero. For the wave surface records of fixed-point observations, the wave height is the height difference between the significant wave peak on one side of the road zero and the significant wave valley on the other side. The wave height observed at a fixed point follows a certain distribution law. In statistical analysis, the distribution of wave height is explained by the occurrence rate and cumulative rate. In the theoretical analysis, a distribution function is used, which gives the probability that the wave height appears in a certain range. In practice, the average wave height of some wave rates is often used, that is, the effective wave height and the cumulative wave height of 1/10 of the large wave height, that is, the cumulative rate of 1% and 5% corresponds to the wave height, as well as the root mean square wave height and average wave height. From the analysis of the wave spectrum and the relationship between the wave elements, the relationships between various wave heights and spectra are obtained. ^[1]

The characteristics of China's offshore wave periodic distribution are similar to the wave height. The northern part is smaller than the southern part. The seasonal distribution of the average period in each place is not changed. Generally, the annual average period of the coastal areas of the Bohai and Yellow Sea is 2.0-4.5 s. Between s, the coast of Fujian and Guangdong in the East China Sea is between 4.2 and 9.8 s, and the coast of the South China Sea is between 4.5 and 7.5 s, and the coast of Hainan Island is about 4.0 s. ^[2]

Offshore wave height distribution in China: The average wave height in the coastal areas of the Bohai and Yellow Seas is relatively small. Among them, the annual average wave height at the Qianliyan station in the southern Shandong Peninsula is the largest at 0.qm. The average annual wave heights of Laoshan Station, Dachen Island and Nanji Island in the coastal waters of Zhejiang Province are above 1 m. The annual average wave height of Beihuo Station in northern Fujian can reach 1.3 m. The wave height in the South China Sea is smaller than that in the East China Sea. The annual average wave height of Zhouzhou Station is 1.0 m. In addition to the annual average wave height of Dongfang Station along the coast of Hainan Island, the remaining stations are about 0.8 m, and the Xisha Islands sea area is 1.3 m.

The maximum wave height of the Bohai and Yellow Sea coasts is about 5 m, of which Beibei Station is 6.2 m, which is the largest in the sea area. The East China Sea coast was affected by the typhoon during the typhoon prevailing period, and the maximum wave height was the largest. Taishan along the coast of Fujian is 9.9 m, Beibei is 14.9 m, and Dazha is 14.8 m. The maximum wave height of individual stations along the Guangdong coast of the South China Sea exceeds 10 m, such as Boga 10.6 m and about 5 m along the coast of Hainan Island. ^[2]