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Impact of internal waves on sound propagation off Bhimilipatnam, east coast of India

DRS at CSIR-National Institute of Oceanography

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Title Impact of internal waves on sound propagation off Bhimilipatnam, east coast of India
 
Creator Sridevi, B.
Murty, T.V.R.
Sadhuram, Y.
Rao, M.M.M.
Maneesha, K.
SujithKumar, S.
Prasanna, P.L.
 
Subject Low frequency
Internal waves
Thermistor chain
GM model
Acoustic simulation
 
Description Internal waves (IW) are identified off Bhimilipatnam, east coast of India, from the time series CTD (hourly interval)and thermistor chain data (2 min interval) collected during 23-25 Feb 2007.The measurements were carried out at 94m water depth on the continental shelf edge. These datasets are used to describe the characteristics of IW and their impact on acoustic fields. Garrett and Munk (GM) model has been used to predict the characteristics of low frequency (LF) IW with space and time. Active IW are seen in the layers54m-94 m with a velocity of 0.548 km h sup(-1) and the wavelengths of the order of 0.03 km-21.8km. The model could capture the IW features in the thermocline region accurately than at the bottom.This could be due to the limitation of the model which considers linearity. High frequency IW observed at the bottom could be due to the advection of tidal currents over the shallow irregular bottom in the presence of stratification. The study emphasizes linear IW rather than transient non-linear waves induced by tidal interaction with topography. Acoustic simulation results for low frequency IW field reveal that the intensity loss anomaly of eigenrays was found to be 2.86 dB-15.59 dB in the water column and maximum(38.48dB) was observed at the bottom due to the bottom interaction. Our results are well compared with those reported earlier from simulation and acoustic field experiments in the Northern IndianOcean.
 
Date 2010-06-14T10:16:26Z
2010-06-14T10:16:26Z
2010
 
Type Journal Article
 
Identifier Estuarine, Coastal and Shelf Science, vol.88(2); 249-259
no
http://drs.nio.org/drs/handle/2264/3632
 
Language en
 
Relation Estuar_Coast_Shelf_Sci_88_249.jpg
 
Rights An edited version of this paper was published by Elsevier. Copyright [2010] Elsevier
 
Publisher Elsevier