Stochastic modelling of the Caspian Sea level fluctuations

Fluctuations of the Caspian Sea level have been treated as a stochastic process influenced by rainfall and ambient temperature. A dynamic relation in time has been established between the monthly average of sea level, rainfall and temperature at the gauging station of Anzali, Iran. It was found that the present sea level,Z(t) is related to previous sea levels, as well as, present and past values of rainfall,R(t), and temperature,T(t), via a transfer function, which quantifies the relationship. While the effect of temperature on the fluctuations of the sea level is seasonal and relatively complicated, that of rainfall is seasonal and more simple.