Evaluation of the effect of saline and fresh water interference on sound speed variation in the basin of Anzali port

Effect of saline and fresh water interference on sound speed variation in the basin of Anzali port has been evaluated. The research is based on the analysis of measured data of various physical parameters of sea water in the vicinity of Anzali port. Also, the effects of saline water of the Caspian Sea and fresh water imported from wetland on the changes in the sound speed in the access channel of Anzali port have been discussed. The data collecting operation was performed by a CTD profiler of the physical parameters of the seawater in fixed stations with a maximum depth of 18 meters in both warm and cold seasons. Results showed that sound speed changed between 1514 and 1511 m/s in the summer. While range of variation in the cold season, was between 1438 (at the surface) and 1454 m/s at 10 m depth. Variation of the sound speed during warm season was affected by water temperature. During cold season, variations of sound speed were under effect of water salinity and, sea saline and wetland fresh water interference. In comparison the results with previous measurements, it is observed that saline and freshwater interference on physical structure of water column and sound speed is considerable in cold season.