Abstract
A long-duration set of wave observations is reported, conducted in the coastal region of south-eastern Sakhalin Island in the Sea of Okhotsk using bottom-mounted pressure sensors, during both ice-free conditions and while sea ice was present. Although one instrument was not able to be recovered, the two remaining high-precision instruments—device ▪ located close to the shoreline and ▪ situated 7.5km seaward in the south-easterly direction—provided time series sampled at 1s allowing wave periods from 2s to 20min to be detected and spectrally analysed. The time series reveal intriguing significant differences between open water periods and times when sea ice covered the surface: e.g. preferential resonant frequencies appear in seastate energy density spectra during episodes of sizeable swell when sea ice is present but not when it is absent; and what is believed to be a trapped edge wave of approximately 11min period in open water, increases in period to 11.8min when the sea ice is there. Although, no technical mathematical theory is advanced, the authors speculate on potential explanations for these anomalies and invite readers to provide alternative hypotheses.
•Bottom-mounted pressure sensor data of ocean waves off Sakhalin Island are examined.•Wave periods from 2 s to 20 min were observed and analysed spectrally.•Edge waves were detected during open water conditions and when sea ice was present.•Energy spectra exposed resonant frequencies due to swell in the presence of sea ice.•Qualitative descriptions are given to explain attributes of each observed phenomenon.