台风"莎莉嘉"过境期间某泻湖内波浪特征分析

通过在某岛礁泻湖内布置ADCP波流测量仪器,采集到2016年21号台风"莎莉嘉"期间的波浪数据.结合布置在泻湖口处风速仪的风实测数据,本文对该时间段内的波浪特征进行分析.由波浪统计数据分析发现有义波高随时间的变化趋势与风速的变化趋势高度重合;谱峰周期的变化则要晚于风速的变化;谱峰方向在台风起主导作用期间与风向高度一致.通过分析多个无因次参数以及对风浪和涌浪进行分离发现测点与台风中心距离开始变大的这个时间点有着重要的意义.在该时间点,波长开始变长,波浪由无限水深波浪转变为有限水深波浪.一些波浪特征值,比如谱峰周期、a/L,也发生比较大的变化.此后在七级风半径不再覆盖测点时,该处波浪由风浪转变为涌浪.对波浪谱进行分析发现,在台风主导期间,其谱为单峰谱,其余时间则为双峰谱.

Characteristics of waves in an atollduring typhoon "Sarika"

The wave data due to No. 1621 typhoon "Sarika" were obtained by ADCP in an atoll. In this paper, the characteristics of waves are analyzed against the wind data, which were measured using the anemorumbometer deployed at the entrance of the atoll. Some conclusions are obtained from the wave statistics.The significant wave heights share the similar trend with wind speed, while the peak period lags behind the trend.The direction of waves and winds are almost the same when "Sarika" played a dominant role in this area. It is found that the timingis important for waves when the distance between gauging point and typhoon center increased. At this time, the lengths of waves became larger; and the waves traveled into finite-depth waves from infinite-depth waves. Some parameters, among which are peak period,kdanda/L changed quickly at this point. After that, the swell replaced the wind-wave to be the dominant component of the waves when the gauging point was no longer covered by the radiusof the moderate gate. At the end of this paper, the shapesof energy spectra are discussed. The results show that the spectra have only one peak when "Sarika" is close to the gauging point; while double peaks appear during other times.