Towards AUV-based iceberg profiling and gouging survey in arctic sea: The first Japanese under-ice AUV deployment in Okhotsk Sea

In this paper, we present an AUV-based strategy for iceberg profiling and seabed gouge survey, and report the results of under-ice AUV dives conducted in Okhotsk Sea. In our strategy, a cruising AUV equipped with multiple MBESs and optical cameras achieves iceberg profiling and seabed gouge survey simultaneously, passing beneath the bottom of an iceberg. Since our AUV-based iceberg profiling and gouge survey are highly challenging missions carrying a higher safety risk, as a preliminary skirmish towards the Arctic sea mission, we conducted under-ice survey dives in ice-covered Okhotsk Sea. During these survey dives conducted in March 2012, we deployed an AUV "Aqua-Explorer 2000a" for profiling the bottoms of drifting ice-floes in an upward-looking manner. Aqua-Explorer 2000a is a cruising AUV developed and owned by Institute of Industrial Science, the University of Tokyo. Two dives were completed successfully as the under-ice survey mission. After finishing the dives, we could profile the ice-floes by using highresolution subsurface topography obtained by an MBES, and generate the photo mosaic of ice-floes along the vehicle's tracks. The dives are successful first steps towards AUV-based fully automatic iceberg profiling and gouge survey in Arctic sea.