Study of large-scale currents in west of south Caspian sea by field and satellite data

In this research using field data of temperature، salinity and density at stations near the Caspian Sea، South West، to be related two cruises has been study the large-scale currents. Geostrophic current caused balance due to the pressure gradient force and Coriolis force and is a major factor in the development of large scale currents. After analyzing data، the speed and direction of these currents were calculated using satellite images. Aviso satellite images with spatial resolution 0. 25° was obtained. Calculations for five vertical sections in the West South Caspian Sea was performed using Excel software. The depth profile of Geostrophic currents in each of these sections was obtained. In South-West Caspian region، the mean velocity of the currents by field data in summer 5. 85 cm /s، and in winter 15 cm /s is calculated. The direction of these currents averaging 285 degrees in summer and 44 degrees in the winter to be obtain. Currents counterclockwise in the summer، according to satellite images to speeds 4. 5 cm/s، in winter eastern and counterclockwise currents with speeds up to 8 cm/s has been shown. Current speed (the magnitude of the vectors) indicates that the flow rate is more moderate in winter، the reason can be difference in density due to increased river flows (especially the Volga)، precipitation، wind، and the result will be noted.