Topographic effects on current variability in the Caspian Sea

Abstract

[1] Satellite-derived surface height fields reveal that variability in the central and southern basins of the Caspian Sea is correlated with topography. Consistently, empirical orthogonal functions from current meter data from the southern basin are aligned with the isobaths. In addition, the gravest mode, which accounts for over 80% of the variance, has an equivalent barotropic structure in the vertical. To what extent this variability can be modeled using a linear analytical model is examined. The latter assumes equivalent barotropic flow aligned with the geostrophic contours, which in turn are dominated by the topography. With ECMWF winds and ETOPO2 topography, the model yields surface height deviations which are significantly correlated with satellite-derived estimates on seasonal and longer time scales in the central basin. The model is somewhat less successful in the southern basin, where the stratification is stronger. Nevertheless, the results are encouraging, given the extreme simplicity of the model.

Caspian Sea and Black Sea Response to Greenhouse Warming in a High‐Resolution Global Climate Model

“…The barotropic gyre circulation in the Caspian Sea has three distinct features: an anti-cyclonic circulation in the northern basin (Figure 2d), which is driven by the prevailing negative wind stress curl (Figure 2a and Figure S3), and two strong cyclonic circulations in the deep central and southern basins, which are driven by a combination of positive wind stress curl and topographic effects (Ghaffari et al, 2013;Figures 2a and 2d, Text S2, and Figure S3). Other factors that contribute to the intensification of the barotropic circulation in the deeper parts of the Caspian Sea include the so-called JEBAR effect (joint effect of baroclinicity and bottom relief) (Sarkisyan, 2006).…”

Remote Surveillance of Differential Deformation for Kazakhstan Offshore Kashagan Oilfield Using Microwave Satellite Remote Sensing

“…Currents in the Caspian Sea are primarily wind-induced, with wind speeds and directions being the major shaping factors [22][23][24][25]. The shape and topography of the seashore and seabed of the Caspian Sea also exert a substantial influence on the currents [26].…”