Wave Height Distributions and Rogue Waves in the Eastern Mediterranean

Sagi Knobler,Rotem Cohen,Dan Liberzon,Daniel Bar

doi:10.3390/jmse9060660

Abstract

There is a lack of scientific knowledge about the physical sea characteristics of the eastern part of the Mediterranean Sea. The current work offers a comprehensive view of wave fields in southern Israel waters covering a period between January 2017 and June 2018. The analyzed data were collected by a meteorological buoy providing wind and wave parameters. As expected for this area, the strongest storm events occurred throughout October–April. In this paper, we analyze the buoy data following two main objectives—identifying the most appropriate statistical distribution model and examining wave data in search of rogue wave presence. The objectives were accomplished by comparing a number of models suitable for deep seawater waves. The Tayfun–Fedele third-order model showed the best agreement with the tail of the empirical wave height distribution. The examination of different statistical thresholds for the identification of rogue waves resulted in the detection of 109 unique waves, all of relatively low height. The characteristics of the detected rogue waves were examined, revealing that the majority of them presented crest-to-trough symmetry. This finding calls for a reevaluation of the crest amplitude being equal to or above 1.25, the significant wave height threshold which assumes rogue waves carry most of their energy in the crest.

Highlights

The estimated crest amplitude was between 5.1–6.4 m, satisfying the rogue wave statistical threshold
The standard threshold for identifying a rogue wave is a wave with a height larger than twice the significant height [6,26,27,28] or wave height larger than eight times the standard deviation (STD) of the instantaneous elevation fluctuation ση [29]. Another threshold that we examined was a wave crest amplitude larger than 1.25 times the significant height, which assumes that the main energy of the rogue wave is carried by the crest [23,26]
Motivated by the lack of sufficient insight and driven by the need for estimation of possible risks posed by extreme events, the current work provides an overview of the eastern Mediterranean Sea water wavefield behavior over a period of a year and a half, starting in January 2017

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Reported on a 10.32 m high rogue wave measured by a Datawell Directional Waverider buoy moored at 85 m at the Black Sea. Sulisz et al (2016) [13] analyzed data recorded by Datawell Directional Waverider buoy, moored at 20.5 m depth in the southern part of the Baltic Sea. During the 1996–2002 period they have found numerous waves answering rogue wave statistical thresholds, most reaching up to 6.2 m height, and the highest detected extreme waves of up to 12 m. The estimated crest amplitude was between 5.1–6.4 m, satisfying the rogue wave statistical threshold To this day, the sole observational study of rogue waves near the coast of Israel has been reported by [18], indicating a possible occurrence of a rogue wave during a large storm of January 2018 by analyzing waves data provided by a nearshore deployed buoy.

Meteorological

Methods

Results

Table 1the listsratio the maximal height

4–18 May 2018

Conclusions