台风影响下海浪的特征分析

Characteristics of the waves in the effect of tropical cyclone

根据2011年6月和2012年7月海上石油平台(LF13-1)海洋自动站的监测资料,"海马"(1104)、"韦森特"(1208)台风影响下的气象及海洋水文参数变化。其结果表明,台风影响前有效波高一般<1.0m,波周期<6.0s。而在台风影响期间,其浪高平均为5m,最大浪高达9.7m,最大周期为9.5s。风速与波高、波周期正相关,而与波浪数呈负相关。平均风速与有效波高相关系数为0.94。台风中心与测站的距离越近,其波高越大;反之,侧波高越小。风速与波浪相速之比U/C决定了风与波浪的能量转换情况,当U>C时风向波浪输送能量,波浪成长;U<C时,波浪不再能从风能中获得能量,波浪衰减。波陡是一个波浪变化的一个重要参数,当波令C/U>0.5时,波陡随波令增大而减小。

According to monitoring data of marine automatic weather station on offshore oil platforms （LF13-1） in June 2011 and July 2012, meteorological and hydrological parameter variations influenced by the typhoon Haima（1104） and Vicente（1208） are analyzed. The results show that the effective wave height and wave cycle are generally less than 1. 0m and 6. 0s respectively before typhoon arriving. During the typhoon, the average and maximum of wave height is 5m and 9.7m with 9.5s maximum cycle. The relationship among wind speed, wave height and wave period show positive correlation, while it presents negative with wave numbers. The correlation coefficient between average wind speed and effective wave height is 0.94. The closer the distance of typhoon center and the station, the greater the wave height. Conversely, the smaller the lateral wave height. The ratio of wind speed and wave phase velocity （U / C） decides energy conversion between the wind and wave. In the case of U~ C, the wind transports energy to the wave with wave growth. If U is less than C, the wave can no longer gain energy from the wind with wave attenuation. Wave steepness is an important parameter for the wave change. When poring C / U is more than 0.5, the steepness decreases with poring growth.