Mean Sea Surface Model of the Caspian Sea Based on TOPEX/Poseidon and Jason-1 Satellite Altimetry Data

Abstract

AbstractUsually mean sea surface (MSS) is calculated by averaging altimetric measurements of sea surface height (SSH) over a given region and over a given time period. However, in the case of the Caspian Sea this represents a certain challenge and existing MSS models are unacceptable.One of the possible solutions is to analyse the Caspian Sea MSS as task of investigation of space-time variability of equipotential sea surface or SSH without seasonal and synoptic variability. Regional MSS model of the Caspian Sea (GCRAS08 MSS) was calculated according to the following scheme.For satellite altimetry data processing dry tropospheric corrections was calculated on atmospheric pressure from nearest weather stations located along the Caspian Sea costal line. From the TOPEX/Poseidon (T/P) and Jason-1 (J1) satellite altimetry data, the SSH synoptic and seasonal variations for all passes of each repeat cycle were eliminated. In last phase, the GCRAS08 MSS was constructed as a SSH function of latitude, longitude, and time with correction on climatic dynamic topography. For specified time interval SSH was interpolated on grid by radial basis function method.For the first time GCRAS08 MSS model allow to investigate space–time variability of the Caspian Sea level. According to the received results spatial variability of rate of the Caspian Sea level change well correlate with EGM96 gravity anomalies field and the greatest variability is observed in the zone of gravity anomalies gradient maximum.KeywordsGravity AnomalySatellite Altimetry DataRadial Basis Function MethodGeophysical Data RecordGravity Anomaly GradientThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.