Nasser H. Zaker, P. Ghaffari and S. Jamshidi, 2007. Physical Study of the Southern Coastal Waters of the Caspian Sea, off Babolsar, Mazandaran in Iran. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 564 – 569. Gold Coast, Australia, ISSN 0749.0208

Temperature, salinity and density field observations over the period of summer to autumn of 2003 in the eastern part of the southern coast of the Caspian Sea are presented. Field investigations were carried out by CTD profiling and RCM9 time series recording across the southern continental shelf of the Caspian Sea off Babolsar, Mazandaran in Iran. These seasonal scale measurements were conducted for the first time in the southern Caspian Sea adjacent to Iran. The results showed a strong thermocline located between 20m and 50m depths in summer with 15 ^oC temperature decrease across it. In the beginning of autumn, the thickness of the thermocline reduced to 15 m and thermocline was located between 30m and 45m depths. The daily temperature in the surface mixed layer ranged between 25 to 30 ^oC in summer and smoothly decreased to 20 ^oC in late autumn. Below thermocline the temperature ranged between 10.5 ^oC to 7.5 ^oC at 110m depth with small seasonal variation. In summer, outside of the continental shelf, an average salinity of 12.2 and 12.3 was observed above and below the thermocline, respectively. The salinity variation from the sea surface to 110 m depth was less than 0.25. Over the continental shelf salinity ranged between 12.05-12.10 and it was slightly less than that in the similar depth outside of the continental shelf. Vertical density variation, considering small vertical salinity variations, was highly correlated with vertical temperature variations.