Wave height

About: Wave height is a research topic. Over the lifetime, 5920 publications have been published within this topic receiving 100257 citations.

Microseisms and hum from ocean surface gravity waves

Abstract: [1] Ocean waves incident on coasts generate seismic surface waves in three frequency bands via three pathways: direct pressure on the seafloor (primary microseisms, PM), standing waves from interaction of incident and reflected waves (double-frequency microseisms, DF), and swell-transformed infragravity wave interactions (the Earth's seismic hum). Beamforming of USArray seismic data shows that the source azimuths of the generation regions of hum, PM and DF microseisms vary seasonally, consistent with hemispheric storm patterns. The correlation of beam power with wave height over all azimuths is highest in near-coastal waters. Seismic signals generated by waves from Hurricane Irene and from a storm in the Southern Ocean have good spatial and temporal correlation with nearshore wave height and peak period for all three wave-induced seismic signals, suggesting that ocean waves in shallow water commonly excite hum (via infragravity waves), PM, and DF microseisms concurrently.

Wave heights in the 21st century Arctic Ocean simulated with a regional climate model

Abstract: While wave heights globally have been growing over recent decades, observations of their regional trends vary. Simulations of future wave climate can be achieved by coupling wave and climate models. At present, wave heights and their future trends in the Arctic Ocean remain unknown. We use the third-generation wave forecast model WAVEWATCH-III forced by winds and sea ice concentration produced within the regional model HIRHAM, under the anthropogenic scenario SRES-A1B. We find that significant wave height and its extremes will increase over different inner Arctic areas due to reduction of sea ice cover and regional wind intensification in the 21st century. The opposite tendency, with a slight reduction in wave height appears for the Atlantic sector and the Barents Sea. Our results demonstrate the complex wave response in the Arctic Ocean to a combined effect of wind and sea ice forcings in a climate-change scenario during the 21st

The Increasing Wave Height in the North Atlantic Ocean

Abstract: There are indications that the mean significant wave height at Seven Stones Light Vessel has increased in the period 1960–85. This is of considerable interest for the design of offshore structures and for coastal defense. In this note, the authors present new results based on the analysis of a collection of more than 20 000 hand-drawn wave charts. These charts were produced routinely between 1960 and 1988 in a manner that remained essentially unchanged throughout this period. The results are in remarkable agreement with the trend observed at Seven Stones Light Vessel.

Prediction of storm/normal beach profiles

Abstract: Using the results of large‐scale wave tank tests of monochromatic waves breaking on sandy beaches, Larson and Kraus have shown that storm (barred) and normal (nonbarred) equilibrium beach profiles can be segregated in terms of two‐dimensionless parameters, which involve wave and sediment characteristics. Here, by rearranging their results, a single dimensionless parameter is developed that predicts the occurrence of storm or normal profiles. The profile parameter (P=gH02/(w3T)) uses deep‐water wave characteristics to distinguish the two profile types. Using shallow‐water data the shallow‐water Dean number, Hb/(wT) can serve the same purpose. Further, a Froude number representation of the sediment fall velocity, w2/(gH0), is shown to be an important parameter for equilibrium profiles.

Short-term statistics of waves observed in deep water

Abstract: The short?term statistics of 10 million individual waves observed with buoys in deep water have been investigated, corrected for a sample?rate bias, and normalized with the standard deviation of the surface elevation (the range of normalized wave heights is 0 < H < 10). The observed normalized trough depths are found to be Rayleigh distributed with near?perfect scaling. The normalized crest heights are also Rayleigh distributed but 3% higher than given by the conventional Rayleigh distribution. The observed normalized wave heights are not well predicted by the conventional Rayleigh distribution (overprediction by 9.5% on average), but they are very well predicted by Rayleigh?like distributions obtained from linear theories and by an empirical Weibull distribution (errors <1.5%). These linear theories also properly predict the observed monotonic variation of the normalized wave heights with the (de?)correlation between crest height and trough depth. The theoretical Rayleigh?like distributions may therefore be preferred over the empirical Weibull distribution and certainly over the conventional Rayleigh distribution. The values of the observed expected maximum wave height (normalized) as a function of duration are consistent with these findings. To inspect nonlinear effects, the buoy observations were supplemented with 10,000 waves observed with laser altimeters mounted on a fixed platform (0 < H< 7). The (normalized) crest heights thus observed are typically 5% higher than those observed with the buoys, whereas the (normalized) trough depths are typically 12% shallower. The distribution of the normalized wave heights thus observed is practically identical to the distribution observed with the buoys. These findings suggest that crest heights and trough depths are affected by nonlinear effects, but wave heights are not. One wave in our buoy observations may qualify as a freak wave.