基于Radon变换获取东沙群岛附近三个内孤立波的传播速度

Calculation of the velocities of three internal solitary waves around Dongsha Islands based on Radon transform

由于大振幅非线性内波对东沙群岛附近的海上石油平台具有很大的破坏性,已有多名学者对该海域的非线性内波的传播波速进行了研究。主要根据2009年6月24日15时40分至25日16时40分"科学一号"考察船在东沙岛东北部陆架上K106站进行的长达25 h的X波段雷达、温度链、ADCP同步观测数据,在该海域利用Radon变换技术获取了本次观测到的内孤立波的传播速度。利用孤立波到达前30 min的ADCP流速值,计算得到内波传播方向上的背景流大小为0.04 m/s。最终得出6月24日22时30分时的内孤立波传播速度为3.04 m/s,传播方向约为297°;6月25日8时30分的内孤立波传播速度为2.73 m/s,传播方向约为289°;6月25日12时内孤立波的传播速度为2.59 m/s,传播方向约为283°。第一个孤立波与后两个孤立波,在振幅和速度大小上存在明显不同,其生成机制也可能不同。

Because of the damage of the nonlinear internal waves （NIWs） with enough big amplitudes to the oil drilling platform around Dongsha Islands, the velocities of these NIWs had been studied by some researchers. Continuous observation of a day from 15 ： 40 on June 24 to 16 ： 40 on June 25, 2009 was made from the R/V Science 1 anchored at the position K106 in the vicinity of the continental slope northeast to the Dongsha Islands. The onboard X-band radar, thermistor chains and ADCP were used during this in situ observation. In this paper, the Radon transform was first used to obtain the velocity of the internal solitary wave （ISW） around Dongsha Islands. According to the current velocity from ADCP during thirty minutes ahead of the arriving of the ISW, the background current speed was calculated as 0.04 m/s in the propagating direction of the ISW. The speed of the ISW at 22 ： 30 on June 24 was equal to 3.04 m/s, and it＇s propagating diredtion was about 297 degree. The velocity of ISW at 8 ： 30 on June 25 was about 2.73 m/s, and it＇s propagating direction was about 289 degree. The velocity of ISW at 12 ： 00 on June 25 was about 2.59m/s, and it＇s propagating direction was about 283 degree. The first ISW was obviously different at the amplitude and speed with the last two ISWs, and they maybe had different generation mechanisms.