Site and frequency dependence of ambient noise in the Northeastern Pacific Ocean

Abstract

One‐hour averages of omidirectional ambient noise measurements at 60 and 165 Hz are analyzed for two nearby, deep ocean sites in the Northeastern Pacific during February and March 1981. Site A is a high noise site and is located near major east–west shipping lanes and near major Pacific storm paths. Site B is a lower noise site and is located approximately 450 nm from site A away from major shipping lanes and near major Pacific storm paths. The site and frequency dependence of ambient noise is found to be highly variable with shipping noise being totally dominant at 60 Hz at site A and storm noise being totally dominant at 165 Hz at site B. Both shipping and storm noise can dominate the 165‐Hz site A or 60‐Hz site B noise levels depending on weather conditions. Storms have a possible indirect effect on shipping noise, since very low noise periods occur in between storms, especially when the storm passes nearby the site. A limited number of WMO ships sampled indicate that ships slow down or stay in port du...