Features of Seasonal Variability of Tidal Sea-level Oscillations in the Russian Arctic Seas
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ures of Seasonal Variability of Tidal Sea-level Oscillations in the Russian Arctic Seas M. E. Kulikova*, I. P. Medvedeva, and A. T. Kondrinb a
Shirshov Institute of Oceanology, Russian Academy of Sciences, Nakhimovskii pr. 36, Moscow, 117997 Russia b Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991 Russia *e-mail: [email protected] Received October 9, 2018 Revised October 18, 2019 Accepted December 17, 2019
Abstract—Tides play an important role in the mesoscale sea level variability in the Arctic seas. A distinctive feature of tides in this region is the seasonal variability of harmonic constants, which is caused by changes in hydrometeorological conditions during a year. Based on the analysis of long-term hourly sea-level observations in the White, Chukchi, and Laptev seas, the seasonal variability of the main tidal harmonic constants and some nonharmonic tidal characteristics are studied. The use of multiyear observation series allowed calculating the mean amplitudes and phases of tidal harmonics in certain months with high precision and estimating their interannual variability. Significant differences are also found in the pattern and magnitude of seasonal variability both between stations and between the White Sea and the Eastern Arctic.
DOI: 10.3103/S1068373920060047 Keywords: Tide, seasonal variability, Arctic seas, ice cover
1. INTRODUCTION Semidiurnal tides penetrating from the Atlantic Ocean dominate in the Arctic Ocean. The semidiurnal tidal wave comes to the seas washing the Russian Arctic coast in two ways: from the west along the coast of the Barents and Kara seas and from the north through the Arctic basin. Tides partly penetrate from the Pacific Ocean through the Bering Strait to the Chukchi Sea. The diurnal tide, unlike semidiurnal one, is mainly natural and is formed inside the Arctic Ocean [11, 13, 15]. The highest magnitude of tides is reached in the White Sea (up to 9.8 m during the spring tide [6]) and decreases from west to east along the coast of the Eastern Arctic seas: the Laptev–East Siberian–Chukchi seas, where the value of tidal oscillations does not exceed 1–1.5 m. However, their contribution to the total sea-level fluctuations remains significant. A distinctive feature of the tidal regime in the Arctic Ocean is the seasonal variability of harmonic constants, which is caused by seasonal changes in the sea ice extent [11]. V.Yu. Vize [1] was one of the first to notice this feature of tides: he derived a dependence of changes in tide magnitude on ice conditions and wind regime. The features of seasonal changes in the Arctic tide were also considered in the papers by Russian and foreign researchers [2–4, 14, 17, 22]. The authors of [17] used numerical modeling to demonstrate that the relative variability of the tidal amplitude in the polar regions can make up to 5–10%. It is shown there that there are two main factors inducing the seasonal variability of barotropic tide. The first factor is seasonal changes in stratification on the continental shelf which affect
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