Short Term Measurements of Omnidirectional Ambient Noise in the Southwest Atlantic during January 1981
NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY STENNIS SPACE CENTER MS
Pagination or Media Count:
Short-term omnidirectional measurements of ambient noise below 1 kHz were made for 14 deep-water stations in the Southwest Atlantic off the coast of South America during January 1981. At the lower frequencies 10 to 150 Hz the noise levels agree with the middle range of the prediction curves for normal shipping densities in the northern oceans as reported by Wenz 1962. No consistent major geographical or physiographic dependence of the ambient noise levels was found for these reported measurements. The levels reported here for this South Atlantic region are generally higher than those found for the South Pacific regions. This result was unexpected as the total shipping in the southern ocean basins is considerably less than that in the northern ocean basis. One possible explanation of why the noise levels are high is that the sources from a high density shipping lane along the east coast of South America may have been effectively coupled to the main propagation paths in the deep sound channel.