Observations of sound-speed fluctuations in the western Philippine Sea in the spring of 2009
Colosi, John A.
Van Uffelen, Lora J.
Cornuelle, Bruce D.
Dzieciuch, Matthew A.
Worcester, Peter F.
Dushaw, Brian D.
Ramp, Steven R.
MetadataShow full item record
As an aid to understanding long-range acoustic propagation in the Philippine Sea, statistical and phenomenological descriptions of sound-speed variations were developed. Two moorings of oceanographic sensors located in the western Philippine Sea in the spring of 2009 were used to track constant potential-density surfaces (isopycnals) and constant potential-temperature surfaces (isotherms) in the depth range 120–2000 m. The vertical displacements of these surfaces are used to estimate sound-speed fluctuations from internal waves, while temperature/salinity variability along isopycnals are used to estimate sound-speed fluctuations from intrusive structure often termed spice. Frequency spectra and vertical covariance functions are used to describe the space-time scales of the displacements and spiciness. Internal-wave contributions from diurnal and semi-diurnal internal tides and the diffuse internal-wave field [related to the Garrett–Munk (GM) spectrum] are found to dominate the sound-speed variability. Spice fluctuations are weak in comparison. The internal wave and spice frequency spectra have similar form in the upper ocean but are markedly different below 170-m depth. Diffuse internal-wave mode spectra show a form similar to the GM model, while internal-tide mode spectra scale as mode number to the minus two power. Spice decorrelates rapidly with depth, with a typical correlation scale of tens of meters.
The article of record as published may be found at http://dx.doi.org/10.1121/1.4818784
Showing items related by title, author, creator and subject.
Horizontal anisotropy and seasonal variation of acoustic fluctuations observed during the 2010–2011 Philippine Sea experiment Marwoto, Bambang (Monterey, California. Naval Postgraduate School, 2015-12);The anisotropic ocean environment will lead to variability of ocean acoustic travel time. The variability of travel times comes from several ocean dynamical processes, including eddies, internal tides, and stochastic ...
Wickham, J.B.; Bird, A.A.; Mooers, C.N.K. (Pergamon Journals Ltd., 1987);Based on two years (July 1978–June 1980) of current meter array measurements and bimonthly STD/XBT transects over the continental margin off central California, the mean California Undercurrent has a jet-like core in excess ...
Breaker, Laurence C.; Mooers, Christopher N.K. (1986);Mesoscale variability off the Central California coast is strongly influenced by coastal upwelling and related processes. Off Point Sur, there is significant space-time variability in oceanic properties over periods of ...