Abstract
A long data set of wave measurements is discussed, collected by means of bottom-mounted pressure recorders located on the shelf off the coast of south-east Sakhalin Island when the Sea of Okhotsk in the vicinity was free of ice, covered by drift ice composed of loose ice floes and ice cakes that had migrated south, or blanketed by a sheet of shore fast sea ice and drift ice. Coastally trapped, barotropic edge waves, leaky wave modes and infragravity waves detected in the data are analyzed using spectral methods—including gain and phase comparisons between the sites where devices were deployed, supported by coherence plots. As well as preferentially eliminating noise and systematically low pass filtering waves to deliver a stabilizing influence, spectrograms suggest that the presence of sea ice also affects the attributes of longer oscillations, e.g. infragravity waves and consequently those arising from the passage of leaky modes offshore and trapped edge waves. The gain and an apparent monotonically increasing phase difference between two nearshore sites are respectively investigated using a well-established solution for how the standing leaky wave envelope decays with distance from the shore and a conceptual model of synchronization.
•A 9-month-long set of wave data from bottom-mounted pressure recorders off south-east Sakhalin Island is discussed.•Whether sea ice is absent or present, spectral methods reveal infragravity waves, trapped edge modes and leaky waves.•Average period and the bandwidth of oscillations increases if sea ice is present, either as drift ice or consolidated ice.•Gain between two sensors placed normally to the shore fits the customary Bessel function decay curve.•Phase drift between two sensors is examined using a van der Pol oscillator as a conceptual model of synchronization.