статья в журнале

En

Regional Studies in Marine Science

ISSN:23524855

2024

10.1016/j.rsma.2023.103326

EINBJJ

Seiches are long standing waves typical of enclosed and semi-enclosed basins. It is shown that they can be generated in bays by long-period waves coming from open sea through an entry. An interaction between adjacent bays may extend the number of seiche modes in these bays. Kruglaya Bay is widely used for recreational purposes. We measured sea level variations in Kruglaya Bay in August-October, 2022 by means of a cost-effective and robust autonomous sea-level recorder designed and assembled in Marine Hydrophysical Institute. Measurements were conducted based on an ultra-sound JSN-SR04T sensor. SWASH, a numerical high-resolution model, was used to simulate dissipating free oscillations in a system of connected shallow semi-enclosed bays initiated by long waves incoming from the open sea. A spectral analysis of measured sea level fluctuations was used to identify resonant periods of local seiches in Kruglaya Bay. Estimate periods of oscillations that correspond to incoming long waves from the neighbouring bays were obtained using the results of mathematical modeling. The performed wavelet analysis permitted to identify situations when local resonant oscillations were initiated before wind intensification (which manifested as an increase in energy at the high-frequency part of the spectrum). An intense fundamental mode (also known as the ‘Helmholtz mode’ of a semi-enclosed oscillating basin) of Kruglaya Bay (period around 14 min) was identified both in measurements and the numerical simulation. The power spectra of the sea level oscillations in Kruglaya Bay also showed significant peaks at the periods of fundamental modes of the neighbouring bays. Besides, periods of the Black Sea seiches (1.25 h and 2.5 h) were identified from the observations. © 2023 Elsevier B.V.

Black Sea, Helmholtz mode, Seiche, Sevastopol, SSH oscillations

2024-02-07 11:34:17