High-frequency sea level oscillations in the Mediterranean and their connection to synoptic patterns

2015 ◽  
Vol 137 ◽  
pp. 284-298 ◽  
Author(s):  
Jadranka Šepić ◽  
Ivica Vilibić ◽  
Amaury Lafon ◽  
Loïc Macheboeuf ◽  
Zvonko Ivanović
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Synoptic Patterns ◽  
Sea Level Oscillations ◽  
The Mediterranean

Estimating contribution of high-frequency sea-level oscillations to the extreme sea levels in the Adriatic Sea

2021 ◽  
Author(s):  
Krešimir Ruić ◽  
Jadranka Šepić ◽  
Maja Karlović ◽  
Iva Međugorac
Keyword(s):  
Time Series ◽  
Sea Level ◽  
High Frequency ◽  
Adriatic Sea ◽  
Tide Gauge ◽  
Data Series ◽  
Sea Levels ◽  
Short Period ◽  
Extreme Sea Levels ◽  
Sea Level Oscillations

<p>Extreme sea levels are known to hit the Adriatic Sea and to occasionally cause floods that produce severe material damage. Whereas the contribution of longer-period (T > 2 h) sea-level oscillations to the phenomena has been well researched, the contribution of the shorter period (T < 2 h) oscillations is yet to be determined. With this aim, data of 1-min sampling resolution were collected for 20 tide gauges, 10 located at the Italian (north and west) and 10 at the Croatian (east) Adriatic coast. Analyses were done on time series of 3 to 15 years length, with the latest data coming from 2020, and with longer data series available for the Croatian coast. Sea level data were thoroughly checked, and spurious data were removed. </p><p>For each station, extreme sea levels were defined as events during which sea level surpasses its 99.9 percentile value. The contribution of short-period oscillations to extremes was then estimated from corresponding high-frequency (T < 2 h) series. Additionally, for four Croatian tide gauge stations (Rovinj, Bakar, Split, and Dubrovnik), for period of 1956-2004, extreme sea levels were also determined from the hourly sea level time series, with the contribution of short-period oscillations visually estimated from the original tide gauge charts.  </p><p>Spatial and temporal distribution of contribution of short-period sea-level oscillations to the extreme sea level in the Adriatic were estimated. It was shown that short-period sea-level oscillation can significantly contribute to the overall extremes and should be considered when estimating flooding levels. </p>

scholarly journals Characterisation of low-frequency sea level oscillations in the Mediterranean sea

2019 ◽  
pp. 121-133
Author(s):  
Vesna Bertoncelj ◽  
Matjaž Ličer ◽  
Dušan Žagar ◽  
Davide Bonaldo
Keyword(s):  
Spectral Analysis ◽  
Mediterranean Sea ◽  
Sea Level ◽  
Mediterranean Basin ◽  
Adriatic Sea ◽  
Low Frequency ◽  
Storm Event ◽  
Sea Level Oscillations ◽  
The Mediterranean ◽  
The Mediterranean Basin

Implementing adequate defences for low-lying coastal area against coastal flooding requires thorough knowledge of all potential influences leading to increased sea levels, including low-frequency sea level oscillations. We present and describe several methods applicable for the analysis of low-frequency sea level oscillations in the Mediterranean Sea: wavelet analysis, spectral analysis, moving-periodogram analysis, and rotary spectral analysis. These methods were applied for characterisation of subinertial sea level oscillations with periods greater of the period of inertial oscillation (18 hours in the Northern Adriatic Sea) on measured sea surface elevations and current velocities in the Mediterranean Sea. Preliminary analysis was performed on observations of a storm event in the Adriatic Sea at the end of January and the beginning of February 2014, revealing a peak in the frequency spectrum in the frequency band between 0.3−0.4 day−1. Further analysis was done on long-term tide gauge measurements available for 62 stations in the Mediterranean basin. The application of the selected methods provided a preliminary set of seasonal occurrences and durations of subinertial oscillation. This sets the ground for further investigation into the propagation of low-frequency sea level oscillations throughout the Mediterranean basin and for characterisation of the mechanisms triggering the process, including with regard to climate change.

Operational tool for characterizing high-frequency sea level oscillations

2020 ◽  
Author(s):  
Javier García-Valdecasas ◽  
Begoña Pérez Gómez ◽  
Rafael Molina ◽  
Alberto Rodríguez ◽  
David Rodríguez ◽  
...  
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Sea Level Oscillations ◽  
Operational Tool

Extreme sea level oscillations in the Sea of Japan caused by typhoons Maysak and Haishen in September 2020

2021 ◽  
Author(s):  
Daria Smirnova ◽  
Igor Medvedev ◽  
Alexander Rabinovich ◽  
Jadranka Šepić
Keyword(s):  
Sea Level ◽  
Sea Of Japan ◽  
High Frequency ◽  
Storm Surges ◽  
Water Area ◽  
Statistical Characteristics ◽  
The Sea Of Japan ◽  
Infragravity Waves ◽  
Relative Contribution ◽  
Sea Level Oscillations

<p>Two hazardous typhoons, Maysak and Haishen, in September 2020 produced extreme sea level oscillations in the Sea of Japan. These typhoons generated three different types of sea level variations: 1) storm surges (with typical periods from several hours to 1.5 days), 2) extreme seiches (with periods from a few minutes to several tens of minutes), and 3) storm-generated infragravity waves (with periods up to 3-5 min). The data from eleven tide gauges on Russian, Korean, and Japanese coasts were used to examine the properties of these oscillations. The relative contribution of the three separate sea level components and their statistical characteristics (duration, wave heights, and periods) were estimated. The periods of the main eigen modes of individual bays and harbours in the Sea of Japan were estimated based on spectral analysis of longterm background records at the corresponding sites. The results of wavelet analysis show the frequency properties and the temporal evolution of individual sea level components. We found that high-frequency sea level oscillations at stations Preobrazheniye and Rudnaya Pristan have a “white noise” spectrum, caused by the dominance of infragravity waves. A high correlation was detected between the variance of high-frequency sea level oscillations at these stations and the significant wind wave height evaluated from ERA5 for this water area.</p>

scholarly journals A survey of strong high-frequency sea level oscillations along the US East Coast between 2006 and 2011

2013 ◽  
Vol 13 (2) ◽  
pp. 473-482 ◽  
Author(s):  
S. Pasquet ◽  
I. Vilibić ◽  
J. Šepić
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
East Coast ◽  
Level Data ◽  
The Us ◽  
Sea Level Oscillations ◽  
Wave Heights ◽  
Generation Mechanisms ◽  
Future Work ◽  
Us East Coast

Abstract. A systematic survey of high-frequency sea level oscillations (<6 h) measured between 2006 and 2011 along the US East Coast is performed. Raw 1-min resolution sea level data is used. After performing a data quality check, the nine most intense events, with maximum recorded wave heights ranging from 40 to 100 cm, are identified. Focusing on three of these events enables us to recognize two different generation mechanisms: (i) topographically-trapped edge waves which are found to be a significant contributor to the strongest observed oscillations, and (ii) standing waves, which occur over enclosed shallow waters and may result in significant wave heights of up to 100 cm. A reproduction of the observed oscillations is a part of a future work, which will include an assessment of a generating force in the atmosphere, allowing for a better prevention of potential flooding along the US East Coast.

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