Spectrum of mesoscale sea level oscillations in the northern Black Sea: Tides, seiches, and inertial oscillations


Cite item

Full Text

Open Access Open Access
Restricted Access Access granted
Restricted Access Subscription Access

Abstract

Long-term data from 23 tide gauges were used to analyze the spectrum of mesoscale sea level variability of the Black Sea. The tides have sharp spectral peaks, and they are detected at diurnal and semidiurnal frequencies for all stations. A local wide spectral peak associated with inertial oscillations is located between the diurnal and semidiurnal tidal peaks. This peak is well known in the spectra of the current velocity variations of the Black Sea, but in the sea level spectrum it has been identified for the first time. At frequencies of >3 cpd, sea level spectra of the Black Sea have (1) wide maxima in the continuous spectrum, which correspond to the main eigenmodes of the sea with periods of 5.6, 4.8, 4.1, and 3.1 h, and (2) sharp peaks of radiational harmonics S3, S4, S5, and S6. The periods of seiches calculated in this study are close to the periods of eigenmodes of the Black Sea, obtained by the numerical modeling of other authors. The main factors influencing the formation of radiational tides in the Black Sea are presumably breezes and runoff from large rivers. The significant predominance of a harmonic with frequency of 5 cpd (S5) over other radiational harmonics is caused by the influence of an eigenmode, with a frequency of about 5 cpd. The proximity of the periods of these oscillations leads to resonant amplification and to a corresponding increase in amplitude of the radiational harmonic S5.

About the authors

I. P. Medvedev

Shirshov Institute of Oceanology

Author for correspondence.
Email: medvedev@ocean.ru
Russian Federation, Moscow

E. A. Kulikov

Shirshov Institute of Oceanology

Email: medvedev@ocean.ru
Russian Federation, Moscow

Supplementary files

Supplementary Files
Action
1. JATS XML

Copyright (c) 2016 Pleiades Publishing, Inc.