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Objective mapping of temperature field by stochastic inverse method using acoustic tomography experimental data of eastern Arabian Sea

DRS at CSIR-National Institute of Oceanography

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Title Objective mapping of temperature field by stochastic inverse method using acoustic tomography experimental data of eastern Arabian Sea
 
Creator Murty, T.V.R.
Rao, M.M.M.
Sadhuram, Y.
 
Subject acoustic tomography
temperature fields
stochastic processes
oceanographic data
 
Description An acoustic transmission experiment was conducted in the eastern Arabian Sea along 12.5 degrees N latitude for a duration of ten days (2-12 May, 1993), with two transceiver systems deployed on deep sea moorings, separated by a range of 270.92 km. The data are revisited for objective mapping of the temperature fields using Stochastic Inverse Method. Hourly reciprocal transmissions were carried with time lag of 30 minutes between each direction. From the multipath arrival patterns, significant peaks corresponding to the predicted ray arrivals were identified and travel time perturbations of the most stable Eigen rays enabled reconstruction of temperature anomaly from the sound velocity perturbations using stochastic inverse method. For formulation of stochastic inverse, generation of data-data and model-data covariance matrices are needed for computing the modal amplitudes to operate on observed time perturbations to estimate the sound velocity perturbations. For present simulation, the dependence of travel time on the oceanic sound velocity has been calculated using ray paths traced by computer with mean profile and vertical and horizontal velocity structures were modeled as a combination of Empirical Orthogonal Functions (EOFs) from insitu CTD data in the study area. A linear relation was used to transform sound speed perturbation in the vertical plane to temperature perturbations, for the first four days of transmission, following Munk and Wunsch (1979). The 2-D temperature anomaly derived from the six hourly mean travel-time data showed a gradual warming of the top layers, significant of diurnal variability and intrusion of Red sea water
 
Date 2008-01-31T11:04:59Z
2008-01-31T11:04:59Z
2007
 
Type Conference Article
 
Identifier METOC - 2007. Proceedings of the National Symposium on 'Emerging Tredns in Meteorology and Oceanography', 21-22 May 2007, eds. Vijayakumar, D.; Jothiraman, V.; Jyothi, A.K.; Satya Prakash; Krishna, M.S.H. 139-146p.
http://drs.nio.org/drs/handle/2264/784
 
Language en
 
Publisher School of Naval Oceanology and Meteorology