A possible connection of Caspian Sea level fluctuations with meteorological factors and seismicity

The Caspian Sea has exhibited significant, wide-range fluctuations that have been traditionally attributed to variations in climatic agents. The objective of this research is to estimate the hydrologic budget and sea surface heights of the Caspian Sea from 1998 to 2005 to assess the contribution of meteorological and geological process to the Caspian Sea level variations. The water budget of the Caspian Sea from 1998 to 2005 was calculated using the state-of-the-art remote sensing techniques and ground-truth data. The Sea Surface heights of the Caspian Sea were constructed from the refined Topex/Poseidon altimetry data. The National Centers for Environmental Prediction/Department of Energy Reanalysis 2 meteorological data provided all the variables necessary for the Penman method to estimate evaporation over the Caspian Sea. The data of the Tropical Rainfall Measuring Mission were utilized to estimate precipitation onto the Caspian Sea. A strong agreement between the water budget residuals and Caspian Sea level variations signifies that Caspian Sea level oscillations for this time window are essentially controlled by climate-related factors. On the other hand, the relatively larger gaps between the water balance residuals and Caspian Sea level heights during 2000 and 2001 may indicate an impact of seismicity on Caspian Sea level oscillations as a result of two major earthquakes on November 25, 2000.