We have conducted sea ice surveys along the Okhotsk sea coast of Hokkaido, Japan using a bottom-mounted IPS and ADCP, thereby measuring the draft and drift speed/direction of sea ice passing over the equipment. In this study, a simulation method is presented that produces the sea ice bottom topography (ice draft profile) considered non-Gaussian process and non-stationary characteristics of sea ice draft, by using only typical normalized spectrum and variance as derived from observed ice draft data.
The Okhotsk Sea coast of Hokkaido is known as the southern limit of sea ice, which forms in high-latitude waters and arrives at Hokkaido between January and March every year. When designing and constructing offshore/coastal structures, pipelines and other underwater and buried structures or winter navigation through pack ice, interaction with sea ice must be fully taken into consideration. It is also necessary to acquire information on the ice bottom topography (ice bottom roughness) in advance for oil spill contingency plans such as prediction of the range of oil spreading under an ice cover or recovery of oil in ice-infested waters. In particular, with the recent progress of oil and natural gas development along the Sakhalin continental shelf, transport of oil and natural gas to Japan by pipelines and vessels as well as accompanying oil spills or other accidents are expected in the future. Therefore, we have conducted sea ice surveys using IPS (Ice Profiling Sonar) and ADCP (Acoustic Doppler Current Profiler) since 2000. Also, sea ice surveys using the same measuring instruments (IPS and ADCP) have been conducted in the northeastern part of Sakhalin (Birch et al.; 1999). Theories and survey methods of these measuring instruments were detailed by Sakikawa et al. (2002), Belliveau et al. (1989) and Birch et al. (1999).