Interannual Variability of Water Exchange Anomalies Between the Northern, Middle and Southern Caspian Based on Satellite Altimetry Data

Abstract

The paper presents the results of estimation of interannual and seasonal variability of water exchange between the Northern, Middle and Southern Caspian Sea based on the TOPEX/Poseidon and Jason–1/2/3 satellite altimetry data. The boundaries between the Caspian Sea sub-basins were taken along the 133 and 209 tracks of the satellites. Temporal variability of surface geostrophic velocities directed perpendicular to the tracks showed that positive values correspond to the southeast direction of the currents, negative values correspond to the northwest direction. It is clearly seen that the main water exchange associated with the Volga River runoff is concentrated along the western coast of the Caspian Sea. In this area, anomalies of geostrophic velocities exceed 20 cm/s. Total water exchange anomalies through the 133 and 209 tracks show seasonal variability with an amplitude up to ±18x105 m3/s for track 133 (a line between the Northern and Middle Caspian) and ±11x105 m3/s for track 209 (a line between the Middle and Southern Caspian). The maximum values of water exchange anomalies were observed in 1993, 1994 and 2012 through 133 track (±16-18x105 m3/s) and in 1993, 1996 and 1997 (±11x105 m3/s) through 209 track.

Self- and Inter-Crossover Points of Jasons’ Missions as New Essential Add-on of Satellite Altimetry in the Sub-Arctic Seas and the Southern Ocean

“…The instantaneous currents can be successfully estimated from two intersecting tracks with a short time lag. A similar approach was tested in the Caspian Sea when calculating water exchange between sub-basins from satellite altimetry data [18,19]. Jasons' HLCs with minimal time lags make such periodic in time along-track estimates at fixed sites more adequate to the problem of monitoring water exchange.…”

“…Nevertheless, 3 SCs and 4 ICs in the White Sea can be used as an alternative source of valuable data on sea level variability, tides, currents, water exchange with the Barents Sea, wind and wave regime, and ice cover [45,46]. Satellite altimetry is already applied to the White Sea in order to study sea level variability, tidal, wind and ice regime [17,18,[47][48][49][50][51].…”