scholarly journals Seasonal and Decadal Variations of the Variance of the Synoptic and Mesoscale Sea Level Variability in the Baltic Sea

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1785
Author(s):  
Igor Medvedev ◽  
Alisa Medvedeva
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Absolute Maximum ◽  
The Baltic Sea ◽  
Sea Level Oscillations ◽  
Gulf Of Riga ◽  
Decadal Variations ◽  
The Baltic ◽  
High Coherence

The present study examines the seasonal and decadal changes of the variance of the synoptic (periods from 2 days to 30 days) and mesoscale (periods from 2 h to 2 days) sea level oscillations in the Baltic Sea. Long-term hourly sea level records were used at 12 tide gauges located in different parts of the sea. We used spectral analysis to estimate the variance for different time scales. The spectral density of sea level oscillations in the Baltic Sea has maximum values in winter when the cyclonic activity in the atmosphere is more intensive. The maximum variances of synoptic σsyn2  and mesoscale σmes2 sea level oscillations are observed in winter, except for the heads of the Gulf of Finland (Gorny Institute) and Gulf of Riga (Pärnu), where the absolute maximum of σsyn2 is reached in November. The variances σsyn2 and σmes2 from November to February are 2–3 and 5 times higher than in the summer. The values of σsyn2 and σmes2 are characterized by high correlation up to 0.7–0.75 with wind variations and atmospheric indices (NAO, AO, and SCAND) in winter and low correlation in summer. The zonal wind and σmes2 in Gorny Institute are characterized by wide areas of high coherence at periods of 0.7–4 years. At Gedser, σsyn2 decreased by 19%, and at Ratan it increased by 17% over 90 years. The values of σmes2 over 90 years increased by 32% at Klagshamn, 36% at Ratan, and up to 60% at Kungsholmsfort.

scholarly journals SEA LEVEL VARIATIONS AT THE LATVIAN COASTAL HYDROLOGIC STATIONS

2016 ◽  
Vol 42 (2) ◽  
pp. 31-38
Author(s):  
Diāna Haritonova
Keyword(s):  
Time Series ◽  
Baltic Sea ◽  
Sea Level ◽  
The Baltic Sea ◽  
Gulf Of Riga ◽  
Water Level Variations ◽  
Sea Level Variations ◽  
Tidal Constituents ◽  
The Baltic ◽  
Tidal Variations

The objective of this paper is to analyse water level variations of the Baltic Sea on the Latvian coast. This is important because the Baltic Sea exhibits a number of remarkable phenomena. One of them is the sea level variations due to winds, complicated by the shape of the gulfs and islands. Under this influence the range of the sea level variations can reach 3 m on the coasts of gulfs. However, the tidal variations of the Baltic Sea range in the order of centimetres only. In the frame of this study, using hourly time series of the sea level records from 7 Latvian coastal hydrologic stations and employing spectral analysis, it has become feasible to identify diurnal and semi-diurnal tide existence both in the Gulf of Riga and in the Baltic Sea at the Latvian coast. Totally 4 main tidal constituents (O1, K1, M2, S2) have been identified. Additionally, nontidal frequency of 5 cycles per day has been detected in the sea level time series of the stations located in the Gulf of Riga.

scholarly journals SEA LEVEL VARIATIONS IN THE GULF OF BOTHNIA

1973 ◽  
Vol 4 (1) ◽  
pp. 41-53 ◽  
Author(s):  
EUGENIE LISITZIN
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Water Volume ◽  
Tide Gauges ◽  
The Baltic Sea ◽  
Land Uplift ◽  
Gulf Of Bothnia ◽  
Sea Level Variations ◽  
The Baltic

An attempt is made to compute the sea level variations in the Gulf of Bothnia, which is isolated by islands and thresholds from the Baltic Sea proper. Observations from tide gauges during the 30-year period 1931–1960 were used. The effect of land uplift was taken into consideration. The maximum annual deviation in water volume from the long-term mean corresponded to 20.74 km3..

scholarly journals Spatio-temporal structure of Baltic free sea level oscillations in barotropic and baroclinic conditions from hydrodynamic modelling

2020 ◽  
Author(s):  
Eugeny A. Zakharchuk ◽  
Natalia Tikhonova ◽  
Elena Zakharova
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Temporal Structure ◽  
Low Frequency ◽  
The Baltic Sea ◽  
Meteorological Forcing ◽  
Sea Level Oscillations ◽  
Spatio Temporal ◽  
The Baltic ◽  
Baroclinic Modes

Abstract. Free sea level oscillations in barotropic and baroclinic conditions were examined using numerical experiments based on a 3D hydrodynamic model of the Baltic Sea. In a barotropic environment, the highest amplitudes of free sea level oscillations are observed in the northern Gulf of Bothnia, eastern Gulf of Finland, and south-western Baltic Sea. In these areas, the maximum variance appears within the frequency range corresponding to periods of 13–44 hr. In a stratified environment, after the cessation of meteorological forcing, water masses relax to the equilibrium state in the form of mesoscale oscillations at the same frequencies as well as in the form of rapidly decaying low-frequency (seasonal) oscillations. The total amplitudes of free baroclinic perturbations are significantly larger than those of barotropic perturbations, reaching 15–17 cm. Contrary to barotropic, oscillations in baroclinic conditions are strongly pronounced in the deep-water areas of the Baltic Sea Proper. Specific spatial patterns of amplitudes and phases of free barotropic and baroclinic sea level oscillations identified them as progressive-standing waves representing barotropic or baroclinic modes of gravity waves and topographic Rossby waves.

scholarly journals Characteristics and Long-Term Variability of Occurrences of Storm Surges in the Baltic Sea

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1679
Author(s):  
Tomasz Wolski ◽  
Bernard Wiśniewski
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Storm Surges ◽  
Coastal Zones ◽  
The Baltic Sea ◽  
Sea Levels ◽  
The Past ◽  
Pressure Area ◽  
The Baltic

Understanding the characteristics of storm surges is especially important in the context of ongoing climate changes, which often lead to catastrophic events in the coastal zones of seas and oceans. For this reason, this paper presents the characteristics of the Baltic Sea storm surges and trends in their occurrences through the past 60 years. The study material was based on hourly sea level readings, spanning the years 1961–2020, retrieved from 45 Baltic Sea tide gauges, as well as air pressure and wind field data. Owing to the analysis and visualization of storm situations, two main types of storm surges were identified and characterized: a surge driven by wind and a surge driven by subpressure associated with an active low pressure area. This paper also discusses a third, mixed type of storm surge. Further analyses have indicated that through the past 60 years in the Baltic Sea, the duration of high sea level has increased by 1/3, the average number of storm surges has increased from 3.1 to 5.5 per year, and the maximum annual sea levels have increased—with a trend value of 0.28 cm/year. These processes, also observed in other marine basins, provide strong evidence for contemporary climate change.

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