Browsing Reprints by Subject "Ambient noise"

Now showing items 21-27 of 27

    • Role of propagation in ambient noise 

      Ross, Donald (NATO. SACLANTCEN, 1982/06)
      To be useful for modern ASW systems design and analyses, descriptions of ambient noise fields must go beyond average omnidirectional spectra and include horizontal and vertical patterns, fluctuations with time, dependencies ...

    • Seismic and hydroacoustic sensing of infrasonic noise in coastal waters 

      Schmalfeldt, Bernd; Rauch, Dieter (NATO. SACLANTCEN, 1982/06)
      Three-component ocean-bottom seismometers with radio links have been deployed in coastal waters to investigate natural and man-made noise at extremely low frequencies. Seismograms from one or up to three sensor stations ...

    • Separation of measured noise coherence matrix into Toeplitz and Hankel parts 

      Harrison, Chris H. (CMRE, 2017/08)
      The cross-spectral density of ocean ambient noise is usually estimated from the product of the complex hydrophone signals, each of which already corresponds to the summed responses of sources from all angles. The true ...

    • Site and frequency dependence of ambient noise in the North Eastern Pacific Ocean 

      Wilson, James H. (NATO. SACLANTCEN, 1982/06)
      One-hour averages of omnidirectional ambient noise measurements at 60 Hz 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 ...

    • Target detection and location with ambient noise 

      Harrison, Chris H. (NURC, 2008/09)
      By placing a vertical array in an ambient noise field and forming an upward and a downward beam one obtains two time series which can be cross correlated to reveal a subbottom profile of the seabed [Siderius et al., J. ...

    • The seamount as a noise barrier 

      Medwin, Herman; Childs, Emily; Jordan, Edgar A. (NATO. SACLANTCEN, 1982/06)
      When the path from a localized noise source is intercepted by a seamount the shielded noise consists of a diffracted component and, if the seamount is close to a sufficiently smooth ocean surface , a multiply-reflected ...

    • Time dependence of infrasonic ambient seafloor noise on a continental shelf 

      Akal, Tuncay; Barbagelata, Alessandro; Guidi, Guido; Snoek, Michael (NATO. SACLANTCEN, 1986/06)
      SACLANTCEN is conducting a long term programme of ambient noise measurements that cover the frequency band from 1 to 100 Hz. A sea-bed sensor consisting of three seismometers and a hydrophone has been deployed close to the ...