Long-term observation of underwater ambient noise at the Ieodo Ocean Research Station in Korea

The Ieodo Ocean Research Station(IORS) is an integrated meteorological and oceanographic observation base which was first constructed in Korea. It was constructed at the Ieodo underwater rock located at a distance of about 150 km to the south-east of the Mara-do, the southernmost island in Korea. The structure is of a fixed jacket type installed at a water depth of 40 m. In order to understand the characteristics of oceanic ambient noise at the station, the ambient noise was measured during 12 months from April 2009 to March 2010. The ambient noise levels at around 300 Hz and 2.5 kHz represented good correlation with the wind speed and significant wave height at IORS. This study also shows that the ambient noise levels above 5 kHz at IORS can be affected by the activity of the snapping shrimp, which is related to the wind speed as well as the seawater temperature.