Several months of seafloor-mounted, pressure-transducer data collected in Mordvinova Bay off the south-east coast of Sakhalin Island in the Sea of Okhotsk are used to interpret surface-gravity waves across a wide range of periods, during intervals when the sea surface was free of sea ice, covered by drift ice of 0.5–1 m thickness, and when both drift ice and consolidated shore fast sea ice was present. A substantial fraction of the data set is shown to be frequency modulated by the diurnal tide and, to a lesser extent, by the semidiurnal tide. Whereas amplitude modulation by the tide has been found in the past in the open ocean, frequency modulation is less common and neither tidal amplitude modulation nor angle modulation have been observed and recorded under sea ice to the authors’ knowledge. Three theoretical oceanographic modalities that could excite the modulation are discussed. Although the sea ice affected the wind-generated waves and swells in the measured energy spectra as predicted, namely by preferential attenuation that causes spectra to become narrower by progressively reducing shorter periods with distance travelled, its effect on waves of longer periods, i.e. 1–10 min, was unanticipated. Oscillations in this band, present as infragravity (IG) waves, leaky waves and an edge wave mode are shown to be affected as well; especially spectral peaks corresponding to IG/leaky waves, which respond to the sea ice by shifting to a slightly longer mean period and becoming broader. The period shift is explained by the spectral sharpening previously mentioned, whilst the broadening is conjectured to be associated with changes to the frequency modulation.

在鄂霍次克海库页岛东南海岸附近的莫德维诺瓦湾收集的数月海底压力传感器数据用于解释大范围时期的表面重力波没有海冰，被 0.5-1 m 厚的流冰覆盖，当同时存在流冰和固结的海岸快速海冰时。数据集的很大一部分显示为受日潮频率调制，并在较小程度上受半日潮的频率调制。尽管过去在公海中发现了潮汐调幅，但频率调制不太常见，据作者所知，在海冰下既没有观察到潮汐调幅，也没有记录到角度调制。讨论了可以激发调制的三种理论海洋学模式。尽管海冰影响了风产生的波浪，并如预测的那样在测量的能量谱中膨胀，即通过优先衰减导致光谱随着行进距离逐渐减少较短的周期而变得更窄，但它对较长周期的波浪的影响，即 1– 10分钟，出乎意料。该频带中的振荡，表现为次重力 (IG) 波、泄漏波和边缘波模式也受到影响；尤其是对应于 IG/泄漏波的光谱峰值，它们通过转移到稍长的平均周期并变得更宽来响应海冰。周期偏移可以通过前面提到的频谱锐化来解释，