Wave Period Research Articles

Resonant soliton molecules, asymmetric solitons and the other diverse wave solutions to the (3 + 1)-dimensional generalized Kudryashov-Sinelshchikov equation for liquid with gas bubbles

Under the present study, we focus on developing some exact solutions of the (3 + 1)-dimensional generalized Kudryashov-Sinelshchikov equation (KSE) for the liquid with gas bubbles. First, the resonant soliton molecules on the different planes are extracted via imposing the velocity resonance condition on the N-soliton solutions that constructed via the Hirota bilinear method. Besides, the asymmetric solitons are also derived by choosing the appropriate parameters. In the end, the diverse kinds of travelling wave solutions including the bright wave, dark wave, singular wave and periodic wave solutions that expressed by the trigonometric, hyperbolic and rational functions are constructed by employing three effective approaches, namely the variational method, Sub-equation method and Wang’s direct mapping method-II. The profiles of the attained solutions are depicted to present the dynamical performances. As far as we all know, the results of this research are all new and can enable us figure out the physical properties of the (3 + 1)-dimensional generalized KSE better.

On a Hirota equation in oceanic fluid mechanics: Double-pole breather-to-soliton transitions

In oceanic fluid mechanics, a Hirota equation describing the propagation of the deep ocean broader-banded waves is studied in this paper. With respect to the envelope of the wave field, we simultaneously take the multi-pole phenomena and breather-to-soliton transitions into account to investigate the double-pole breather-to-soliton transitions via the second-order generalized Darboux transformation. Under certain parameter conditions, double-pole anti-dark solitons, periodic waves, W-shaped solitons and multi-peak solitons are derived, analyzed and graphically illustrated. We perform the asymptotic analysis on the double-pole anti-dark solitons to investigate their interaction properties, e.g., amplitudes, characteristic lines, slopes, phase shifts and position differences. Different from the known double-pole solitons of some other models, the double-pole anti-dark solitons, hereby, indicate that the two soliton components own unequal amplitudes.

Modulation instability and comparative observation of the effect of fractional parameters on new optical soliton solutions of the paraxial wave model

This work focuses on the study of the paraxial wave model with a space–time fractional form. This model has more importance for describing light propagation in nonlinear optical fibers and telecommunication lines. The main aim of this work is to observe the effect of the fractional parameters and compare the truncated M\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M$$\\end{document}-fraction with the beta-fraction, conformable fraction form, and classical form of the PW model. For this observation, we applied the Simplest equation technique to acquire analytical solutions to the space–time (spatiotemporal) M\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M$$\\end{document}-fractional paraxial wave model. We are able to acquire several new optical soliton solutions, including periodic waves, kink-type waves, rogue-type waves, and several novel periodic waves, by providing the appropriate fractional parametric values. These solutions have significance for shedding light on a number of physical phenomena in the realms of optical fiber and communication sciences. The diverse values of fractional parameters and the three-dimensional and contour plot graphs of certain chosen solutions are depicted, which are the most accurate physical characterizations of the outcomes. We also sketch the comparative graph of diverse fractional forms and the classical form of the paraxial wave equation in two-dimensional plots. Consequently, our findings represent an important breakthrough in this complex area and help further develop our comprehension of the behavior of solitons.

Magnetoacoustic waves in spin-1/2 dense quantum degenerate plasma: nonlinear dynamics and dissipative effects

Abstract Within the confines of a two-fluid quantum magnetohydrodynamic model, the investigation of magnetoacoustic shock and solitary waves is conducted in an electron-ion magnetoplasma that considers electrons of spin 1/2. When the plasma system is nonlinearly investigated using the reductive perturbation approach, the Korteweg de Vries-Burgers (KdVB) equation is produced. Sagdeev’s potential is created, revealing the presence of solitary solutions. However, when dissipative terms are included, intriguing physical solutions can be obtained. The KdVB equation is further investigated using the phase plane theory of a planar dynamical system to demonstrate the existence of periodic and solitary wave solutions. Predicting several classes of traveling wave solutions is advantageous due to various phase orbits, which manifest as soliton-shock waves, and oscillatory shock waves. The presence of a magnetic field, the density of electrons and ions, and the kinematic viscosity significantly alter the properties of magnetoacoustic solitary and shock waves. Additionally, electric fields have been identified. The outcomes obtained here can be applied to studying the nature of magnetoacoustic waves that are observed in compact astrophysical environments, where the influence of quantum spin phenomena remains significant, and also in controlled laboratory plasma experiments.

Symmetric doubly periodic gravity-capillary waves with small vorticity

We construct small amplitude gravity-capillary water waves with small nonzero vorticity, in three spatial dimensions, bifurcating from uniform flows. The waves are symmetric, and periodic in both horizontal coordinates. The proof is inspired by Lortz' construction of magnetohydrostatic equilibria in reflection-symmetric toroidal domains [23]. It relies on a global representation of the vorticity as the cross product of two gradients, and on prescribing a functional relationship between the Bernoulli function and the orbital periods of the water particles.The presence of the free surface introduces significant new challenges. In particular, the resulting free boundary problem is not elliptic, and the involved maps incur a loss of regularity under Fréchet differentiation. Nevertheless, we show that a version of the Crandall–Rabinowitz local bifurcation method still applies in this setting, by carefully tracking the loss of regularity.

Physical Experiments Of Wave Attenuation Over Submerged Shellfish Reefs

Globally and across Australia shellfish reef ecosystems have become critically endangered due to decades of overfishing, pollution and dredging (e.g., Beck et al., 2011). In response, the Australian federal government, in partnership with The Nature Conservancy, committed to restoring 60 shellfish reef ecosystems across Australia by building reefs from limestone and recycled shells scattered with juvenile oysters or mussels. Although the primary aim is to promote healthy marine ecosystems and biodiversity, there are strong indications that these restored shellfish reefs may also substantially dissipate ocean waves and provide protection against coastal flooding. Analogies have been drawn with conventional engineering structures (submerged breakwaters, e.g. Dattatri et al., 1978) as well as nearshore shellfish reefs increasingly considered as a nature-based method for coastal resilience against flooding (“living shorelines”, see e.g. Morris et al., 2021). Although the currently restored reefs do present clear similarities, they also have distinct differences that raise questions to whether they can be as effective in dissipating wave energy. Observational data from laboratory or field to verify this is currently lacking. This study aims to quantify the effectiveness of multiple parallel submerged reef structures in relatively deep water in dissipating wave energy. Experiments (1:10 scale) were carried out in a 54-m-long wave flume using 3 reef designs that vary in reef spacing, width and height, representative for shellfish reef ecosystems as recently restored and established across Australia and the US. All designs were subjected to two water depths (0.7 and 1 m on laboratory scale) and 8 (irregular) wave conditions covering 4 peak wave periods and significant wave heights ranging from 0.1 to 0.3 m (lab scale). For the cases with 0.7 m water depth, wave height reduction varied from 10 to 23%, while for the cases with 1 m water depth wave heights generally decreased slightly up to about 5%. The reefs were found to be particularly effective in reducing the largest waves within the timeseries that would have the highest potential of causing coastal impact (e.g., flooding or erosion). In addition, observations obtained with an Acoustic Doppler Velocimeter showed up to 45% reduction of near-bed orbital (rms) velocities, highlighting the potential for these structures to benefit seagrass restoration efforts. Overall, the results of this study show that restored shellfish reefs can reduce incident wave energy and orbital velocities considerably, in particular for relatively high waves in relatively shallow water, and have the potential to be considered in nature-based coastal defense strategies.

On the Existence of Superposed and Superposed-type Real and Complex Elliptic Periodic Waves of KdV Equation

On the Existence of Superposed and Superposed-type Real and Complex Elliptic Periodic Waves of KdV Equation

Statistics of Bubble Plumes Generated by Breaking Surface Waves

AbstractWe examine the dependence of the penetration depth and fractional surface area (e.g., whitecap coverage) of bubble plumes generated by breaking surface waves on various wind and wave parameters over a wide range of sea state conditions in the North Pacific Ocean, including storms with sustained winds up to 22 m s−1 and significant wave heights up to 10 m. Our observations include arrays of freely drifting SWIFT buoys together with shipboard systems, which enabled concurrent high‐resolution measurements of wind, waves, bubble plumes, and turbulence. We estimate bubble plume penetration depth from echograms extending to depths of more than 30 m in a surface‐following reference frame collected by downward‐looking echosounders integrated onboard the buoys. Our observations indicate that mean and maximum bubble plume penetration depths exceed 10 and 30 m beneath the surface during high winds, respectively, with plume residence times of many wave periods. They also establish strong correlations between bubble plume depths and wind speeds, spectral wave steepness, and whitecap coverage. Interestingly, we observe a robust linear correlation between plume depths, when scaled by the total significant wave height, and the inverse of wave age. However, scaled plume depths exhibit non‐monotonic variations with increasing wind speeds. Additionally, we explore the dependencies of the combined observations on various non‐dimensional predictors used for whitecap coverage estimation. This study provides the first field evidence of a direct relation between bubble plume penetration depth and whitecap coverage, suggesting that the volume of bubble plumes could be estimated by remote sensing.

Validation Of An Efficient Non-Hydrostatic Wave Model As A Design Tool For Foreshores In Physical Models

In the design of physical model experiments in coastal engineering, it is common that the construction of a foreshore is necessary to obtain the desired wave conditions at a given location, usually close to a structure being tested. In addition to the commonly used spectral wave parameters to describe the target wave conditions, the wave height distribution and associated parameters (such as Hmax and H2%), wave periods and infra-gravity waves can be important to reproduce properly as well. Wave height distributions are typically important for tests where e.g. wave run-up or wave forces are of interest. Since the construction of foreshores is labour intensive (and thus expensive), it is useful to be able to check a priori whether the target wave conditions are met with a given foreshore design and whether the chosen transition slope does not significantly influence the wave conditions. One way to do this is by using numerical wave models. For a numerical model to be a useful design tool for physical model layouts, the predicted wave transformation (over the foreshore) needs to be sufficiently accurate. One option is to use detailed CFD wave models for this purpose, such as OpenFOAM, which has been shown to accurately reproduce wave transformation (Jacobsen et al., 2015; Jacobsen et al., 2018). CFD models, however, typically feature high computational demand and consequentially computational times in the order of days. This is a significant disadvantage in the context of designing a physical model experiment, for which the layout and configuration is often an iterative process, which would be hampered by overly long computational times. On the other hand, spectral wave models, like SWAN (Booij et al., 1996), are much faster but do not model all the individual waves rendering it unable to model exceedance distributions. As a middle-ground, it seems that the XBeach model (Roelvink et al., 2009) used in its 2-layer non-hydrostatic mode (De Ridder et al., 2021) might present a workable compromise between computational time and accurate representation of the wave transformation. The model has been validated by De Ridder et al. (2021) on bichromatic waves, complex barred beach geometry and a fringing reef for bulk wave parameters and spectral properties. Expanding on earlier validation work, in this work the ability of the XBeach 2-layer non-hydrostatic model (XBeach-nh) to reproduce wave height exceedance distributions over a sloping foreshore is validated using wave flume data, described in Sections 2 and 3. The preliminary results of the validation effort are shown in Section 4.

The effectiveness of vaccination on the COVID-19 epidemic in California

The COVID-19 pandemic has caused overwhelming morbidity, mortality, and hospitalization worldwide, including in the state of California. Vaccination efforts have been an important measure in curtailing the adverse outcomes of COVID-19. To quantify the effectiveness of COVID-19 vaccinations in California, we conducted a retrospective cohort study investigating how vaccination has impacted the extent of COVID-19 contraction, hospitalizations, and death totals. We compared outcomes ofthe Delta Wave, Omicron Wave, and Pre-Delta Period. Vaccinated individuals have far-lower incidence risk ratio (IRR) of and odds of contracting a COVID-19 case (Delta IRR: 0.197) being hospitalized from COVID-19 (Delta IRR: 0.105), and dying from COVID-19 compared with an unvaccinated individual (Delta IRR: 0.0941). The preventive fraction of the unexposed and population-preventive fractions for cases, deaths, and hospitalizations also showed significant proportions. All tests showed P<.001. Vaccination was most effective in the Delta Wave, then in the Omicron Wave, and least effective in the Pre-Delta Period. Deaths were the most prevented outcome, followed by hospitalizations, then cases. This study exposes the massive impact of vaccinations in California in reducing COVID-19 outcomes and the potential for fewer adverse outcomes had there been greater vaccination compliance, demonstrating the need to increase vaccination efforts.

Tropical cyclone wave data assimilation impact on air-ocean-wave coupled Hurricane Harvey (2017) forecast

The impact of surface wave assimilation on hurricane track and intensity forecasts has been investigated using a fully coupled air-ocean-wave tropical cyclone data assimilation and forecast modeling system. A new 3DVAR wave assimilation method in the Navy Coupled Ocean Data Assimilation system (NCODA) maps the 1D wave energy spectra from buoys to 2D directional wave energy spectra using the maximum likelihood method (MLM) and corrects the wave model forecast component directional wave energy spectra. The Coupled Ocean/Atmosphere Mesoscale Prediction System for Tropical Cyclone Prediction (COAMPS-TC) is used to conduct three Hurricane Harvey (2017) air-ocean-wave coupled data assimilation and forecasting experiments with and without the wave data assimilation. Hurricane Harvey traversed through the Western Gulf of Mexico from 24 August to 1 September, 2017 and made landfall in the Texas and Louisiana coast. Validation of track, maximum wind speed, significant wave height, and mean absolute wave periods show wave assimilation of the 1D wave energy spectra from 13 National Data Buoy Center (NDBC) buoys reduced the forecast errors of these parameters compared to experiments without the wave assimilation. In spite of this positive outcome, the wave assimilation is unable to reduce Harvey’s 0-120 h forecast mean wave direction errors and correlation compared to the NDBC buoy time series

Experimental Study On The Effect Of The Wavelength On Wave Overtopping Over Recurved Walls

Wave overtopping phenomenon on vertical breakwaters is influenced by various physical parameters, encompassing wave height, period, water depth at the breakwater, breakwater freeboard, and foreshore steepness. Existing equations for estimating overtopping rates predominantly rely on the relative freeboard (Rc/Hm0) as the key parameter. This study highlights a significant deviation from this conventional approach when utilizing a recurved wall instead of a plain vertical wall, emphasizing the necessity to consider additional parameters, particularly wave period. In our quest for enhanced accuracy in estimating wave overtopping over recurved breakwaters, we have used F'=Rc/ (Hm02 Lp)1/3, as a replacement for the conventional relative freeboard. Comparative analyses reveal that the proposed formulas for both impulsive and non-impulsive waves exhibit superior accuracy compared to existing formulas. Nevertheless, it is noteworthy that, for larger relative freeboards, a robust formula for estimating wave overtopping remains elusive.

Study of hydrodynamic characteristics in oscillating wave surge converter

In the realm of renewable energy, researchers worldwide have been paying close attention to developing the Oscillating Wave Surge Converter (OWSC) device. This device has the potential to harness the power of ocean waves and convert it into a reliable source of clean energy. Hydrodynamic characteristics are essential parameters in developing OWSC devices. Therefore, this research conducted a hydrodynamic study on the OWSC device with variations in ocean wave periods, including T= 1.5, 1.7, 1.9, 2.1, and 2.3. The Boundary Element Method (BEM) describes the interaction between sea waves and floating body structures. This method assumes incompressible, inviscid, and irrotational flow. A numerical approach is used as a calculation method followed by verification and validation to support the level of actualization. The research results showed that the incident wave caused the OWSC device to experience a deviation from its equilibrium position in the form of an oscillating flap inclination angle as a form of hydrodynamic characteristics. The sea wave period correlatedwith the rate of change in flap position over time, including the maximum deviation in the flap angle. As a power plant, the performance of the OWSC device can work at reasonably short-wave period intervals based on the device's ability to produce mechanical power. The highest average mechanical power was achieved in the T= 1.5 period of 34.49 Watts with an efficiency of up to 52.43%. The OWSC device requires a high intensity of wave energy in a short duration to generate optimal mechanical power. It is important to note that optimal mechanical power generation is crucial for the OWSC device to function effectively. Therefore, the device should be placed in a location where the wave energy intensity is consistently high.

The Evolution of Cinemas in Prague from the Second Half of the Twentieth Century: A Contemporary Perspective

The article approaches the situation of Prague cinemas in the second half of the 20th century from the end of the Second World War to the Velvet Revolution within the socio-historical background from the point of view of an architect and a cinephile. The entire text is arranged chronologically in four paragraphs reflecting the contemporary political and social situation. It approximates the post-war period full of ideological ideals, when the construction of a dense network of cinemas became a key element of national renewal, not only in large cities but also in the regions. The following decade brought a paradigmatic shift, when local single-screen cinemas gave way to large cultural houses with multifunctional use (film, theatre, gallery, restaurant, sports facilities, etc.). It deals with the socially relaxed sixties, reflecting the synergy of various artistic disciplines, thanks to which Czechoslovakia presented to the world new artistic disciplines based precisely on film projection – “polyekran” (polyscreen) and “laterna magika” (a combination of projection and performance with live actors). The imaginary culmination of the new wave period was the opening of the luxury cinema 64 U Hradeb, which is given more attention in the text below. Furthermore, the text outlines the situation of cinemas in large Prague housing estates and deals with Czech brutalism in the context of foreign architecture and with the only brutalist cinema still operating today – the Dlabačov cinema. The final part of this article gives a brief overview of the total number of cinemas established in this period in the territory of Prague and a comparison with other European metropolises with a similar socio-cultural background. The research has the ambition to understand and approach how to integrate valuable cinema buildings on the territory of Prague into the daily life of contemporary Prague residents through the investigation of the cinema phenomenon, and the development of cinematography and cinema architecture as such, from its inception to the present day. The general logical processing methods are historical and socio-cultural analysis, architectural and urban research including architectural drawings, photographic documentation and a study of the urban development of the appearance of individual cinemas, comparison and deduction.

Reliability-Based Design Optimization for a Vertical-Type Breakwater with an Emphasis on Sliding, Overturn, and Collapse Failure

To promote the application of reliability-based design within the Korean coastal engineering community, the author conducted reliability analyses and optimized the design of a vertical-type breakwater, considering multiple limit states in the seas off of Pusan and Gunsan – two representative ports in Korea. In this process, rather than relying on design waves of a specific return period, the author intentionally avoided such constraints. Instead, the author characterized the uncertainties associated with wave force, lift force, and overturning moment – key factors significantly influencing the integrity of a vertical-type breakwater. This characterization was achieved by employing a probabilistic model derived from the frequency analysis results of long-term in-situ wave data. The limit state of the vertical-type breakwater encompassed sliding, overturning, and collapse failure, with the close interrelation between wave force, lift force, and moment described using the Nataf joint probability distribution. Simulation results indicate, as expected, that considering only sliding failure underestimates the failure probability. Furthermore, it was shown that the failure probability of vertical-type breakwaters cannot be consistently secured using design waves with a specific return period. In contrast, breakwaters optimally designed to meet the reliability index requirement of &lt;i&gt;β&lt;/i&gt;-3.5 to 4 consistently achieve a consistent failure probability across all sea areas.

Optimization Analysis of the Arrangement of the Submerged Floating Tunnel Subjected to Waves

The motion responses, mooring tensions, and submergence depth are the dominant factors for the arrangement of the Submerged Floating Tunnel (SFT) subjected to waves. Generally, the maximum values of motion responses, mooring tensions, and absolute submergence depth are mainly focused on. In the present study, experiments are implemented to measure the motion responses and mooring tensions of the SFT with different mooring patterns and submergence depths under waves with different characteristic wave heights and periods. In order to evaluate the arrangement of the SFT more effectively and comprehensively, besides the maximum values, several new characteristic parameters are introduced. Such parameters account for the motion responses in the frequency domain, the uniformity of the tension distribution, the length of time during which the cable reaches a relaxed condition during wave action, the KC number, the dimensionless period, the wave height, and the submergence depth. The results from the optimization analysis show the following: according to the characteristic values of motion responses and mooring tensions, the pattern of diagonal cables is better than that of diagonal cables + vertical cables; and within the range of the present experiments, there are optimal dimensionless parameters—the dimensionless submergence depth d0/LP ≥ 0.15, the KC number ≤ 0.8, or the dimensionless wave height Hs/d0 ≤ 0.10—for the condition of which the dynamic responses and mooring tensions vary slightly.

Verification Of New Double Suspention Keofloat To Minimise Wave Height Inaccuracies In A Physical Model Resulting From Rotation In A 3D Wave Agitataion Study

A modification to the Keofloat system has been developed to address the effect that rotation about its vertical axes may have on the quantities effecting measurement accuracy of the system. The effect of rotation was not previously determined and was found to rarely occur in specific locations for some three-dimensional models. Consequently, the Keofloat design was modified from having a single suspension string to a double suspension string supporting it. A single and double suspension string Keofloat was tested in a wave flume to compare the modified Keofloat to what was previously used. Tests were conducted for regular waves between 0.5 mm and 23 mm and wave periods of 0.8 s and 1.6 s. The testing conducted, included two sets of tests, one for direct comparison where rotation was not present and the other where controlled and nonintrusive rotation was generated on the single suspension string Keofloat. The tests show that the double suspension string Keofloat compared extremely good to the single suspension string Keofloat and can reliably be used to measure small waves in a harbour basin where factors causing rotation of the Keofloat might be present.

Physical Modelling Of Rock Bags Under Wave Attack

In 1987, rock bags were developed by Kyowa in Japan to protect against erosion from hydraulic processes in riverine, lake, coastal and marine environments. Since 2020, rock bags have been used as a temporary or emergency coastal protection unit for seawalls on some beaches in Australia (e.g. Wamberal Beach and Collaroy Beach). These structures have typically been built against a pre-existing dune or eroded dune scarp for protection of landward coastal assets. While a limited amount of hydraulic scale modelling has been undertaken for some rock bag applications, their behaviour in shallow water, coastal environments under wave forces had not previously been quantitively evaluated. A two‑stage physical modelling program was carried out to assess the behaviour of rock bags when used in this emerging erosion protection application. As a result of the scale laboratory tests for shallow water seawalls constructed from rock bags, specific results were obtained for a proposed structure at Stockton Beach (Newcastle, Australia) as well as producing generic design information that could be applied at other locations. As expected, the design wave height for rock bag damage (displacement) was found to be inversely proportional to wave period. Preliminary design stability curves were developed for rock bags under monochromatic and irregular wave attack. In addition to displacement, settlement of the rock bags was observed during the modelling, and it is recommended that consideration should be given to vertical settlement over the design life of these structures. Wave runup was also found to be high; this is also an important consideration for future rock bag seawalls in either establishing the design crest level to prevent wave overtopping or adopting and managing a permissible amount of wave overtopping during a design event.

Change in RhoGAP and RhoGEF availability drives transitions in cortical patterning and excitability in Drosophila

Actin cortex patterning and dynamics are critical for cell shape changes. These dynamics undergo transitions during development, often accompanying changes in collective cell behavior. Although mechanisms have been established for individual cells' dynamic behaviors, the mechanisms and specific molecules that result in developmental transitions invivo are still poorly understood. Here, we took advantage of two developmental systems in Drosophila melanogaster to identify conditions that altered cortical patterning and dynamics. We identified a Rho guanine nucleotide exchange factor (RhoGEF) and Rho GTPase activating protein (RhoGAP) pair required for actomyosin waves in egg chambers. Specifically, depletion of the RhoGEF, Ect2, or the RhoGAP, RhoGAP15B, disrupted actomyosin wave induction, and both proteins relocalized from the nucleus to the cortex preceding wave formation. Furthermore, we found that overexpression of a different RhoGEF and RhoGAP pair, RhoGEF2 and Cumberland GAP (C-GAP), resulted in actomyosin waves in the early embryo, during which RhoA activation precedes actomyosin assembly by ∼4 s. We found that C-GAP was recruited to actomyosin waves, and disrupting F-actin polymerization altered the spatial organization of both RhoA signaling and the cytoskeleton in waves. In addition, disrupting F-actin dynamics increased wave period and width, consistent with a possible role for F-actin in promoting delayed negative feedback. Overall, we showed a mechanism involved in inducing actomyosin waves that is essential for oocyte development and is general to other cell types, such as epithelial and syncytial cells.

Sea ice and waves in the Sea of Okhotsk from 1989 to 2012

Coastlines along the Sea of Okhotsk in Hokkaido are the southernmost regions in the northern Pacific Ocean where sea ice reaches the coast. It has been demonstrated that global warming affects and decreases the ice cover area in the Sea of Okhotsk. This study thus aims to investigate the relationship between sea ice and waves in the Sea of Okhotsk by analyzing ice cover area, sea ice volume, significant wave height and significant wave period. Additionally, we made an attempt to clarify trends in ice cover area and sea ice volume from 1989 to 2012 using satellite images. Sea ice volumes in the northern part of the Sea of Okhotsk correlate with significant wave height and significant wave period. Furthermore, ice cover area and sea ice volume have decreased since 2001 or 2002, which may enhance wave action during winter.