Evaluation of Physical Structure and Summertime Stratification in the Coastal Water Column of the Southern Caspian Sea

Results of the field measurements using CTD profiler in the southern coastal waters of the Caspian Sea are presented. The measurements were carried out in Kiyashahr region that is located in the Guilan province, in north of Iran. The observations were done over 13 sampling station with a maximum depth of 90 m depth during a marine cruise in the southern coastal waters of the Caspian Sea. During the marine cruise, CTD probe was released into the seawater column from sea surface to the bottom near 90 m depth. The collected data showed formation a seasonal thermal stratification including surface mixed layer, Thermocline and deep water layer in the water column. Water temperature in the sea surface mixed layer (with 10 m depth) ranged between 29.5-29 oC. At the time of measurement in midsummer, thermocline layer had 30 m thickness and located between 10-40 m depths. Vertical structure of sea water temperature indicated a sharp vertical gradient 20oC across the thermocline. Below the thermocline till sea bottom, seasonal variations of temperature were slight.