Caspian Sea Level Change Observed by Satellite Altimetry

We analyze satellite altimeter observed Caspian Sea level (CSL) changes over the period January 1993 to December 2021 using lake series from Hydroweb project and global sea anomalies (SLA) grids provided by Copernicus Marine Environment Monitoring Service (CMEMS). The two altimeter-based CSL agree well at interannual longer time scales, but show significantly large discrepancies seasonal shorter scales. are found be introduced approximately inverted barometer (IB) correction applied CMEMS SLA Sea. IB or any enclosed lakes needs treated separately ocean correct reference mean pressure. actual effects smaller than those in grids. After applying an improved pressure fields European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 reanalysis atmospheric model, remarkably well. Altimeter a significant decreasing trend on top of strong variations. estimated linear trends −5.37 ± 0.11 −5.40 cm/yr, respectively. Annual amplitudes 17.03 1.33 vs. 15.79 1.30 cm, with nearly same phases. change shows notable acceleration since around 2005, have increased −8.86 0.10 −8.81 respectively two-altimeter series.