Experimental Study on the Impact of Seasonal Sound Speed Variability on Signal Detection Range in Arabian Sea

Abstract

Temporal variability of Signal Detection Range (SDR) with respect to measured noise level and sound speed is examined. An N x 2D acoustic model which included bathymetric variations, was used to study detection ranges for an area in Arabian Sea. Azimuthal and seasonal SDR at octave bands within 500 Hz were determined at different receiver depths. Study shows that seasonal change in sound speed profile resulted in high SDR and noise level in winter at the location. Study also confirms the significant seasonal difference in detection range corresponds to the cut off frequency at 160 Hz. Detection range for a receiver at a depth 40 m is observed to be high across the azimuth and seasons of study.


Model predicted TL Mosaic in winter and summer, at five frequencies and four depths.
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Model predicted TL over the range from source to receiver (60 km) at six frequencies in winter (orange) and summer (blue), receiver depth is 10 m.
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Signal Detection Range (SDR) at 5 selected frequencies and four receiver depths. In each polar plot both summer (solid line) and winter (dotted line) SDR are given.
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