Low-frequency sea level changes in the Caspian Sea: long-term and seasonal trends

The analysis of seasonal and long-term changes the Caspian Sea level examined from historical long time tide gauge data in order to consider influence climate factors on sea this lake system using spectral method. major peak at spectra corresponds annual cycle semiannual oscillations is located next vigorous. Effects different global regional are investigated by signal processing methods. Results show that Siberian High Volga River discharge have considerable effects scales, respectively. Analyzing revealed river significant fluctuations 1-month lag northern central sub-basins 2 months delay for southern sub-basin. results ascending trend evaporation sub-basin, which it main driver decreasing since 1990s.