Numerical modelling of the Caspian Sea tides

• Main Authors: I. P. Medvedev, E. A. Kulikov, I. V. Fine
• Format: Article
• Language: English
• Published: Copernicus Publications 2020-02-01
• Series: Ocean Science
• Online Access: https://www.ocean-sci.net/16/209/2020/os-16-209-2020.pdf

<p>The Caspian Sea is the largest enclosed basin on Earth and a unique subject for the analysis of tidal dynamics. Tides in the basin are produced directly by the tide-generating forces. Using the Princeton Ocean Model (POM), we examine details of the spatial and temporal features of the tidal dynamics in the Caspian Sea. We present tidal charts of the amplitudes and phase lags of the major tidal constituents, together with maps of the form factor, tidal range, and tidal current speed. Semi-diurnal tides in the Caspian Sea are determined by a Taylor amphidromic system with anticlockwise rotation. The largest M<span class="inline-formula">₂</span> amplitude is 6&thinsp;cm and is located in Türkmen Aylagy (called Turkmen Bay hereafter). For the diurnal constituents, the Absheron Peninsula separates two individual amphidromes with anticlockwise rotation in the north and in the south. The maximum K<span class="inline-formula">₁</span> amplitudes (up to 0.7–0.8&thinsp;cm) are located in (1) the south-eastern part of the basin, (2) Türkmenbaşy Gulf, (3) Mangyshlak Bay; and (4) Kizlyar Bay. As a result, the semi-diurnal tides prevail over diurnal tides in the Caspian Sea. The maximum tidal range, of up to 21&thinsp;cm, has been found in Turkmen Bay. The strongest tidal currents have been located in the straits to the north and south of Ogurja Ada, where speeds reach 22 and 19&thinsp;cm&thinsp;s<span class="inline-formula">⁻¹</span>, respectively. Numerical simulations of the tides using different mean sea levels (within a range of 5&thinsp;m) indicate that spatial features of the Caspian Sea tides are strongly sensitive to changes in mean sea level.</p>