Page 27 - \Winter 2015

(a) (b) (c)
Figure 9. Correlation matrix of the acoustic field measured near (a) Ascension Island, (b) Diego Garcia, and (c) Wake Island during the year 2010.
an increase in the levels of ambient noise in those frequency bands that are dominated by anthropogenic sources. The potential of using the CTBTO system to provide an acoustic "weather" counterpart to meteorological weather, which is a temporal and spatial average, more amenable to tracking long term changes should be investigated. Finally, the use of a frequency correlation method to better define ambient noise source functions removes the indistinctness of terms like "shipping" or "seismic events."
Biosketches
David L. Bradley received a Ph.D. in Mechanical Engineering in 1970 from The Catholic University of America. His work career has been a combination of US Navy sup- ported research, Laboratory Direc- torship at the NATO Undersea Re- search Centre, La Spezia, Italy and university research and academic
activity at The Pennsylvania State University, the Applied Research Laboratory. Currently a Professor of Acoustics, he is funded by the Office of Naval Research. He has served as President and Associate Editor for the Acoustical Society of America. A Fellow of the Acoustical Society, he has served on the Executive Council and chaired Society committees.
Stephen M. Nichols is a graduate research assistant at the Applied Re- search Laboratory at The Pennsylva- nia State University. He earned his B.S. in Physics from the University of California, Los Angeles in 2011. He is currently working on his Ph.D. in Acoustics at Penn State. His gradu- ate work is focused on the analysis of
large sets of very low frequency underwater ambient noise, looking primarily at the source mechanisms responsible for creating the ambient noise field.
References
Andrew, R., Howe, B., and Mercer, J. (2011). “Long-time trends in ship traf- fic noise for four sites off the North American West Coast,” Journal of the Acoustical Society of America 129, 642-651.
Andrew, R., Howe, B., Mercer, J., and Dzieciuch, M. (2002). “Ocean ambient sound: Comparing the 1960s with the 1990s for a reciever off the Califor- nia coast,” Acoustics Research Letters Online 3, 65-70.
Auer, M., and Prior, M. K. (2014, September). “A new era of nuclear test verification,” Physics Today, pp. 39-44.
Curtis, K. R., Howe, B. M., and Mercer, J. M. (1999). “Low-frequency ambi- ent sound in the North Pacific: Long time series observations,” Journal of the Acoustical Society of America 106, 3189-3200.
Hawkins,A.D.,andPopper,A.N.(2012).TheEffectsofNoiseonAquatic Life. (Springer).
Hawkins, A. D., and Popper, A. N. (2014, Spring) “Assessing the impact of underwater sounds on fishes and other forms of marine life,” Acoustics To- day, pp. 30-41.
Hughes, B. (1976). “Estimates of underwater sound (and infrasound) pro- duced by nonlinearly interacting ocean waves,” Journal of the Acoustical Society of America 60, 1032-1039.
Ketten, D. R. (2014, Summer). “Sonars and strandings: are beaked whales the aquatic acoustic canary?,” Acoustics Today, pp.46-56.
Lawrence, M. (2004). “Acoustic monitoring of the global ocean for the CTBT,” Proceedings of Acoustics 2004, pp. 455-460.
Lloyd, S. P. (1981). “Underwater sound from surface waves according to the Lighthill-Ribner theory,” Journal of the Acoustical Society of America 69, 425-435.
Longuet-Higgins, M. S. (1950). “A theory on the origin of microseisms,” Philosophical Tranactionsof the Royal Society of London, Series A 243, 1-35.
McCreery, C. S., Duennebier, F. K., and Sutton, G. H. (1993). “Correlation of deep ocean noise (0.4-30 Hz) with wind, and the Holu Spectrum-A worldwide constant,” Journal of the Acoustical Society of America 93, 2639- 2648.
Neukirk, S. L.; Mellinger, D. K.; Moore, S. E.; Klinck, K.; Dziak, R. P. and Goslin, J. (2012). “Sounds from airguns and fin whales recorded in the mid-Atlantic Ocean, 1999-2009,” Journal of the Acoustical Society of Amer- ica 131, 1102-1112.
| 25