Investigation of the effect of outflow intrusion the Persian Gulf to the Oman Sea on the acoustic signal fluctuations

Abstract

Outflow intrusions are often detected in the vertical profiles of temperature and salinity in the ocean (for example, the Red Sea and Persian Gulf outflow into the India Ocean and Oman Sea, respectively). They are being visible by large fluctuations or inversions within the profiles and as zig-zag patterns in the temperature-salinity plots. In this study, first, using the collected salinity and temperature data in the region of the Oman Sea during spring 1996, the sound speed is calculated via Makenzie formula. Then, by plotting the sound speed profile, it was seen that the vertical structure meet anomaly at depth 200 to 400 meter of the profile. Moreover, the effects of presence and absence of the temperature inversion have been examined on the acoustic signal fluctuations with similar boundary conditions using SPARC model at frequency of 100 Hz. The results show that, when the acoustic source is installed below the inversion layer, receivers that are located in the low temperature inversion layer, receive the signal with time delay, and amplitude is greater than that with the absent inversion temperature. Thereby, the present achievements indicate that the outflow intrusion may affect the shapes and delay times of the received signals.