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Wave height
About: Wave height is a research topic. Over the lifetime, 5920 publications have been published within this topic receiving 100257 citations.
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TL;DR: In this paper, an omnidirectional hydrophone was used to measure the ambient noise in 25 logit-filter bands of frequencies ranging from 11 to 2816 Hz for 2 min every 2 h.
Abstract: Ambient sea noise was measured from an omnidirectional hydrophone located in the deep‐ocean environment. The hydrophone is installed in about 2400 f and is suspended 400 ft above the ocean bottom. The results illustrate the time variability and the correlation of deep open‐ocean ambient‐noise spectra with simultaneous wind‐speed and wave‐height measurements recorded during typical winter conditions. Broad‐band ambient noise levels were automatically recorded on magnetic tape for 2 min every 2 h. The average value of ambient‐noise in 25 logit‐filter bands of frequencies ranging from 11 to 2816 Hz was measured for each 2‐min sample. Autocorrelations of ambient‐noise levels, wind speed, and wave height, as well as cross‐correlation of ambient‐noise levels with wind speed and wave heights, are presented. The ambient‐noise spectra show the superposition of two major noise sources. One noise source is suspected to be distant shipping. This noise source predominates in the frequency range between 17 and 112 Hz and shows noise maxima occurring at 20 and 60 Hz. The other noise source is wind dependent and is observed below 17 and above 112 Hz. The variation in the standard deviation as a function of frequency at low wind speeds is suspected to be the result of the superposition of the two noise sources. The correlation coefficient of wind speed or wave height to sea noise varies as a function of frequency and wind‐speed group.
45 citations
TL;DR: In this paper, a series of 22 wave poles having vertical gradations of 7 cm and 11 cm were placed across the surf zone from outside the break point to the swash zone.
Abstract: Observations of wave crest elevation, wave trough elevation, and wave celerity have been made in the surf zone on a natural beach. A series of 22 wave poles having vertical gradations of 7 cm (near shore) and 11 cm (off shore) were placed across the surf zone from outside the break point to the swash zone. Movements of 10 individual waves all having a break point within one wave pole spacing of each other have been photographed, and the data on wave height changes and wave speed changes have been analyzed. Wave celerity within the surf zone, given as a ratio M to solitary wave celerity, shows a systematic increase of wave speeds near the break point to a peak of M ≃ 1.2, thence a decrease farther shoreward to M ≃ 0.8, and finally a second increase where M > 1. Wave height decay after breaking follows the theory of turbulent dissipation recently presented by Sawaragi and Iwata (1974). The wave height to water depth ratio within the surf zone is a function of distance from the break point and ranges from 2.0 to 0.6. The results indicate that the use of linear and nonlinear nonviscous wave theories to quantify surf zone wave characteristics is misleading insofar as quantitative prediction is concerned.
45 citations
TL;DR: In this paper, the effect of CO 2 doubling on the frequency and inten-sity of high wind waves and storm-surge events in the Adriatic Sea is estimated.
Abstract: This study attempts to estimate the effect of CO 2 doubling on the frequency and inten-sity of high wind waves and storm-surge events in the Adriatic Sea. The meteorological forcings werederived from two 30-yr-long time-slice experiments that simulated the global atmospheric circulationin the present and the doubled-CO 2 climate scenarios. These time-slice experiments were carried outby the Danish Meteorological Institute using the ECHAM-4 model at T106 resolution. Unfortunately,the resolution of the T106 wind is inadequate for simulation of the wave field and the storm surge inthe Adriatic Sea, and it results in a gross underevaluation of extreme events. In this study, regionalsurface wind fields have been derived from T106 sea-level-pressure fields by statistical downscaling.Downscaled wind fields have been used to force a wave and an ocean model during the two 30-yr-long simulations. The downscaled wind fields produce a large improvement with respect to the T106fields, but a systematic underestimation with respect to the observed wave height and surge levelsremains present. This shortcoming of the analysis might prevent identification of very intense events.Consequently, extreme-value analysis of the results of the present climate simulation produces val-ues lower than observed, and obviously the same systematic bias is expected in the evaluation of thefuture climate. Some caution is therefore necessary in the interpretation of the results of this study.Nonetheless, the comparison between the present and future climate simulations shows no substan-tial change in the extreme surge level and a decrease in the extreme wave height.KEY WORDS: Regional climate scenarios · Storm surges · Wave height · Extremes · CO
45 citations
TL;DR: In this article, a Poisson-Gumbel compound extreme value distribution is proposed as the frequency influenced by a typhoon agrees well with the Poisson distribution, and the wave heights under the typhoon condition agree well with Gumbel distribution.
Abstract: A Poisson-Gumbel compound extreme value distribution is suggested as the frequency influenced by a typhoon agrees well with the Poisson distribution, and the wave heights under the typhoon condition agree well with the Gumbel distribution. The results obtained by such a distribution are close to those of Pearson type III curve and Gumbel curve, and the method shows its primary advantage in the stability of its computing results even in the condition of inadequate observed data. A large number of statistical analogous experiments were completed on an electronic computer. It shows that in the case of a long return period, the results obtained by this new method are more consistent with the experimental data than those computed by Gumbel curve. This method can be used for predicting design wave heights and wind velocities in ocean engineering.
45 citations
TL;DR: In this article, the authors presented a comprehensive numerical simulation of a point wave absorber in deep water and analyzed the effects of wave characteristics on energy conversion and device efficiency, including wave height and wave period, as well as the device diameter, draft and damping coefficient.
Abstract: In this paper, we present a comprehensive numerical simulation of a point wave absorber in deep water. Analyses are performed in both the frequency and time domains. The converter is a two-body floating-point absorber (FPA) with one degree of freedom in the heave direction. Its two parts are connected by a linear mass-spring-damper system. The commercial ANSYS-AQWA software used in this study performs well in considering validations. The velocity potential is obtained by assuming incompressible and irrotational flow. As such, we investigated the effects of wave characteristics on energy conversion and device efficiency, including wave height and wave period, as well as the device diameter, draft, geometry, and damping coefficient. To validate the model, we compared our numerical results with those from similar experiments. Our study results can clearly help to maximize the converter’s efficiency when considering specific conditions.
45 citations