scholarly journals Near Real-Time Monitoring of Significant Sea Wave Height through Microseism Recordings: Analysis of an Exceptional Sea Storm Event

2021 ◽  
Vol 9 (3) ◽  
pp. 319
Author(s):  
Laura Cutroneo ◽  
Gabriele Ferretti ◽  
Simone Barani ◽  
Davide Scafidi ◽  
Francesco De Leo ◽  
...  
Keyword(s):  
Predictive Model ◽  
Wave Height ◽  
Extreme Events ◽  
Correction Term ◽  
High Energy ◽  
Storm Event ◽  
Sea Waves ◽  
Ligurian Sea ◽  
Sea Storm ◽  
Sea Wave

Microseisms are used to estimate significant sea wave heights (Hs) in different parts of the world and also during extreme events (e.g., typhoons and hurricanes), as they are generated by the effect of sea waves on the sea bottom and are strictly related to the wave height. On 29 October 2018, an exceptional sea storm event (the Adrian storm) occurred in the Ligurian Sea (NW Mediterranean Sea), producing severe damage to coastal constructions and infrastructures. However, the microseism measured at seismic stations located near the coast did not show equivalent high energy, thus resulting in a severe underestimation of the Hs predicted. In the present study, the Adrian storm was compared to other sea storms that have occurred in the Ligurian Sea in recent decades. The aim of this paper is to statistically examine the distinctive peculiarities of the Adrian storm in order to find new parameters to insert in the empirical models used in the procedure recently implemented for monitoring of Hs through microseism recordings in the Ligurian Sea, improving the effectiveness in Hs estimates in cases of extreme events that do not produce high-energy microseisms. The results show that the additional parameters to be taken into account into the predictive model are the atmospheric pressure gradient and the wind intensity. A correction term is finally proposed and applied to the predictive model to significantly reduce the Hs underestimation.

Near real-time monitoring of significant sea wave height through microseism recordings: An application in the Ligurian Sea (Italy)

2018 ◽  
Vol 165 ◽  
pp. 185-194 ◽  
Author(s):  
Gabriele Ferretti ◽  
Simone Barani ◽  
Davide Scafidi ◽  
Marco Capello ◽  
Laura Cutroneo ◽  
...  
Keyword(s):  
Real Time ◽  
Wave Height ◽  
Real Time Monitoring ◽  
Ligurian Sea ◽  
Sea Wave

scholarly journals Characteristic of Sea Waves Southern Batam City waters-Northen Lingga District waters

2020 ◽  
Vol 4 (2) ◽  
pp. 367-371
Author(s):  
Soedrajad Haryo Adji ◽  
Risandi Dwirama Putra ◽  
Mario Putra Suhana ◽  
Try Febrianto ◽  
Chandra Joei Koenawan
Keyword(s):  
Wave Height ◽  
Geographical Location ◽  
Ocean Waves ◽  
Shore Protection ◽  
Sea Waves ◽  
Characteristic Analysis ◽  
Ship Traffic ◽  
Shipping Traffic ◽  
The Stability ◽  
Sea Wave

The southern Batam City sea and northern of Lingga District sea are often used by fishing locations and shipping traffic from Batam City to Lingga District. Southern of Batam City sea-northen Lingga District sea have uncertain sea wave conditions that can affect the stability of ship traffic. The purpose of this study is to determine characteristic of sea waves along with wind speed and directions. Characteristic analysis of ocean waves using the SPM (Shore Protection Manual) method from wind direction and speed data in 2018. The height of ocean waves in the northen Batam City sea-southern Lingga District during 2018 is 2.59 meters with periods of 8.47 s up to 0.005 m with a period of 0.39 s. The average wave height in 2018 is 0.69 m with sea wave characteristic patterns still following seasonal wind conditions. The highest sea wave height conditions are in the northern season due to the geographical location of the southern Batam City sea-southern Lingga District sea in the Northern Hemisphere.

scholarly journals Analysis of Dangerous Sea States in the Northwestern Mediterranean Area

2021 ◽  
Vol 9 (4) ◽  
pp. 422
Author(s):  
Alessio Innocenti ◽  
Miguel Onorato ◽  
Carlo Brandini
Keyword(s):  
Extreme Events ◽  
Mediterranean Area ◽  
Rayleigh Distribution ◽  
Surface Elevation ◽  
Wave Steepness ◽  
Sea Waves ◽  
Operational Forecasts ◽  
Long Time ◽  
Simulated Field

Extreme sea waves, although rare, can be notably dangerous when associated with energetic sea states and can generate risks for the navigation. In the last few years, they have been the object of extensive research from the scientific community that helped with understanding the main physical aspects; however, the estimate of extreme waves probability in operational forecasts is still debated. In this study, we analyzed a number of sea-states that occurred in a precise area of the Mediterranean sea, near the location of a reported accident, with the objective of relating the probability of extreme events with different sea state conditions. For this purpose, we performed phase-resolving simulations of wave spectra obtained from a WaveWatch III hindcast, using a Higher Order Spectral Method. We produced statistics of the sea-surface elevation field, calculating crest distributions and the probability of extreme events from the analysis of a long time-series of the surface elevation. We found a good matching between the distributions of the numerically simulated field and theory, namely Tayfun second- and third- order ones, in contrast with a significant underestimate given by the Rayleigh distribution. We then related spectral quantities like angular spreading and wave steepness to the probability of occurrence of extreme events finding an enhanced probability for high mean steepness seas and narrow spectra, in accordance with literature results, finding also that the case study of the reported accident was not amongst the most dangerous. Finally, we related the skewness and kurtosis of the surface elevation to the wave steepness to explain the discrepancy between theoretical and numerical distributions.

scholarly journals Environmental controls on surf zone injuries on high-energy beaches

2019 ◽  
Vol 19 (10) ◽  
pp. 2183-2205 ◽  
Author(s):  
Bruno Castelle ◽  
Tim Scott ◽  
Rob Brander ◽  
Jak McCarroll ◽  
Arthur Robinet ◽  
...  
Keyword(s):  
Wave Height ◽  
Surf Zone ◽  
High Tide ◽  
High Energy ◽  
Water Levels ◽  
Small Scale ◽  
Beach Morphology ◽  
Environmental Controls ◽  
Flow Activity ◽  
Incident Waves

Abstract. The two primary causes of surf zone injuries (SZIs) worldwide, including fatal drowning and severe spinal injuries, are rip currents (rips) and shore-break waves. SZIs also result from surfing and bodyboarding activity. In this paper we address the primary environmental controls on SZIs along the high-energy meso–macro-tidal surf beach coast of southwestern France. A total of 2523 SZIs recorded by lifeguards over 186 sample days during the summers of 2007, 2009 and 2015 were combined with measured and/or hindcast weather, wave, tide, and beach morphology data. All SZIs occurred disproportionately on warm sunny days with low wind, likely because of increased beachgoer numbers and hazard exposure. Relationships were strongest for shore-break- and rip-related SZIs and weakest for surfing-related SZIs, the latter being also unaffected by tidal stage or range. Therefore, the analysis focused on bathers. More shore-break-related SZIs occur during shore-normal incident waves with average to below-average wave height (significant wave height, Hs = 0.75–1.5 m) and around higher water levels and large tide ranges when waves break on the steepest section of the beach. In contrast, more rip-related drownings occur near neap low tide, coinciding with maximised channel rip flow activity, under shore-normal incident waves with Hs >1.25 m and mean wave periods longer than 5 s. Additional drowning incidents occurred at spring high tide, presumably due to small-scale swash rips. The composite wave and tide parameters proposed by Scott et al. (2014) are key controlling factors determining SZI occurrence, although the risk ranges are not necessarily transferable to all sites. Summer beach and surf zone morphology is interannually highly variable, which is critical to SZI patterns. The upper beach slope can vary from 0.06 to 0.18 between summers, resulting in low and high shore-break-related SZIs, respectively. Summers with coast-wide highly (weakly) developed rip channels also result in widespread (scarce) rip-related drowning incidents. With life risk defined in terms of the number of people exposed to life threatening hazards at a beach, the ability of morphodynamic models to simulate primary beach morphology characteristics a few weeks or months in advance is therefore of paramount importance for predicting the primary surf zone life risks along this coast.

scholarly journals The effects of the big storm events in the first half of 2015 on the radiation belts observed by EPT/PROBA-V

2016 ◽  
Vol 34 (1) ◽  
pp. 75-84 ◽  
Author(s):  
V. Pierrard ◽  
G. Lopez Rosson
Keyword(s):  
Charged Particle ◽  
High Resolution ◽  
Geomagnetic Storm ◽  
Energetic Particle ◽  
High Energy ◽  
Radiation Belts ◽  
Radiation Environment ◽  
Storm Event ◽  
Storm Events ◽  
Particle Radiation

Abstract. With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, associated to the penetration of high energy fluxes at L < 2 completely filling the slot region. After 10 days, the formation of a new slot around L = 2.8 for electrons of 500–600 keV separates the outer belt from the belt extending at other longitudes than the South Atlantic Anomaly. Two other major events appeared in January and June 2015, again with injections of electrons in the inner belt, contrary to what was observed in 2013 and 2014. These observations open many perspectives to better understand the source and loss mechanisms, and particularly concerning the formation of three belts.

A Method to Implement the Random Signals for Time Varying Offshore Wave Height During Storm Condition in an Intra-Wave Period Wave Model

2006 ◽  
Author(s):  
Yuliang Zhu ◽  
Shunqi Pan ◽  
Premanandan T. Fernando ◽  
Xiaoyan Zhou
Keyword(s):  
Wave Height ◽  
Wave Model ◽  
Peak Frequency ◽  
Wave Period ◽  
Storm Event ◽  
Time Varying ◽  
Wave Heights ◽  
Offshore Wave ◽  
Storm Condition ◽  
Period Wave

In this paper, a method to implement the surface elevation at the offshore boundary during storm conditions is presented in the intra-wave period wave model. At storm condition, the offshore incident significant wave height is time varying. In the case of time varying incident wave height, the JONSWAP energy spectrum can be manipulated as follows: H1/32s(f). s(f) is the energy density function for a unit wave height. During a storm event not only the offshore boundary significant wave heights but also the peak frequency varies. If we choose a mean peak frequency during a storm event, s(f) can be calculated for the mean peak frequency for the storm event. The amplitudes of the component waves for the random signals are calculated from the unit energy density function s(f), and the phase angle of the component wave, So we can numerically generate surface elevation time series for the time varying offshore wave heights. The method was verified in the intra-wave period wave model using field measurements at Sea Palling site Norfolk UK.

scholarly journals STATISTICAL PROPERTIES OF THE MAXIMUM RUN OF IRREGULAR SEA WAVES

1988 ◽  
Vol 1 (21) ◽  
pp. 48 ◽  
Author(s):  
Akira Kimura
Keyword(s):  
Probability Distribution ◽  
Wave Height ◽  
Probability Distributions ◽  
Confidence Regions ◽  
Statistical Properties ◽  
Irregular Waves ◽  
Sea Waves ◽  
Sea State ◽  
Irregular Wave ◽  
Distribution Of The Maximum

The probability distribution of the maximum run of irregular wave height is introduced theoretically. Probability distributions for the 2nd maximum, 3rd maximum and further maximum runs are also introduced. Their statistical properties, including the means and their confidence regions, are applied to the verification of experiments with irregular waves in the realization of a "severe sea state" in the test.

scholarly journals A New Solution for Sea Wave Energy Harvesting, the Proposal of an Ironless Linear Generator

2020 ◽  
Vol 8 (2) ◽  
pp. 93 ◽  
Author(s):  
Domenico Curto ◽  
Alessia Viola ◽  
Vincenzo Franzitta ◽  
Marco Trapanese ◽  
Fabio Cardona
Keyword(s):  
Wave Energy ◽  
Magnetic Force ◽  
Vertical Motion ◽  
Small Islands ◽  
Sea Waves ◽  
Energy Converter ◽  
Energy Potential ◽  
Linear Generator ◽  
Three Phase ◽  
Sea Wave

The paper investigates an innovative ironless linear generator, installable inside a wave energy converter, in order to produce electricity from sea waves. This energy source is considered strategic for the future, especially in small islands; however, this technology is still far from the commercial phase. Considering the wave energy potential of the Mediterranean Sea, a first prototype of the electrical linear generator was realized at the Department of Engineering of Palermo University. This machine can be run by a two-floating buoys system, able to produce a linear vertical motion. The main goal of this paper is the investigation of the advantages and the disadvantages of the utilization of steel materials to realize the stator of linear generators. Thus, starting from the prototype, the authors analyzed the effects produced by the replacement of steel in the stator with a non-magnetic material. For comparison, the authors evaluated the amplitude of no-load voltages, using a three-phase connection scheme, and the amplitude of the magnetic force produced by the interaction of magnets with the stator. Both aspects were evaluated through numerical simulations and mathematical models.

scholarly journals VERIFICATION OF KIMURA's THEORY FOR WAVE GROUP STATISTICS

1984 ◽  
Vol 1 (19) ◽  
pp. 43 ◽  
Author(s):  
J.A. Battjes ◽  
G.Ph. Van Vledder
Keyword(s):  
Wave Motion ◽  
Random Phase ◽  
Wave Generation ◽  
Original Form ◽  
Wave Group ◽  
Sea Waves ◽  
Wave Groups ◽  
Wave Groupiness ◽  
Active Wave ◽  
Sea Wave

North Sea wave records, obtained in conditions of active wave generation, have been analyzed with respect to the distribution of the length of wave groups. The results are compared to a theory by Kimura, in its original form as well as with the addition of a new spectral wave groupiness parameter, based on the theory of Gaussian processes. The results lend support to the validity of Kimura's theory, this in turn implies further evidence that the phenomenon of wave groups in sea waves can by and large be explained, both qualitatively and quantitatively, in terms of the linear, random phase model for the wave motion, even in conditions of active wave generation.

Tow Forces for Emergency Towing of Containerships

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Vladimir Shigunov ◽  
Thomas E. Schellin
Keyword(s):  
Wave Height ◽  
Current Speed ◽  
Sea Waves ◽  
Wave Direction ◽  
Equilibrium Equations ◽  
Significant Wave ◽  
Wind Speeds ◽  
Time Average ◽  
Wave Drift Forces ◽  
Drift Forces

For a series of five containerships of differing capacities (707, 3400, 5300, 14,000, and 18,000 TEU), systematic computations were performed to estimate the tow force required in an emergency. Time-average ship positions with respect to the given waves, wind, and current directions and the corresponding time-average forces were considered. Current speed was considered to include also towing speed. Directionally aligned as well as not aligned wind and waves were investigated. Wave height, wind speed, and wave and wind direction relative to current direction were systematically varied. Wind speeds based on the Beaufort wind force scale corresponded to significant wave heights for a fully arisen sea. Waves were assumed to be irregular short-crested seaways described by a Joint North Sea Wave Observation Project (JONSWAP) spectrum with peak parameter 3.3 and cosine squared directional spreading. For each combination of current speed, wave direction, significant wave height, and peak wave period, the required tow force and the associated drift angle were calculated. Tow force calculations were based on the solution of equilibrium equations in the horizontal plane. A Reynolds-Averaged Navier–Stokes (RANS) solver obtained current and wind forces and moments; and a Rankine source-patch method, drift forces and moments in waves. Tow forces accounted for steady (calm-water) hydrodynamic forces and moments, constant wind forces and moments, and time-average wave drift forces and moments. Rudder and propeller forces and towline forces were neglected.

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