Air-Sea Interactions under the Existence of Opposing Swell

Observed physical and environmental causes of scatter in whitecap coverage values in a fetch‐limited coastal zone

“…This range of steepness values is similar to the range of steepness values of the long waves generated in the laboratory by Mitsuyasu and Yoshida [2005] and includes the critical steepness value of 0.01 noted above. Using the findings of Mitsuyasu and Yoshida [2005], we would therefore expect the shorter wind waves to have an amplified spectral energy for those values of long wave steepness greater than 0.01. At this point, it is important to clarify that the mechanism by which the short wave amplification occurred in the laboratory, as suggested by Mitsuyasu and Yoshida [2005], was via an increase in wind stress due to the presence of the longer swell waves.…”

“…Using the findings of Mitsuyasu and Yoshida [2005], we would therefore expect the shorter wind waves to have an amplified spectral energy for those values of long wave steepness greater than 0.01. At this point, it is important to clarify that the mechanism by which the short wave amplification occurred in the laboratory, as suggested by Mitsuyasu and Yoshida [2005], was via an increase in wind stress due to the presence of the longer swell waves. An increase in spectral energy of the wind waves may also, however, suggest a decrease in energy dissipation through a reduction in wave breaking.…”

“…Figure 10 suggests that the steepness of longer waves had a measurable effect on W at low wind speeds in this study, but it is clear that this observation needs more investigation with better directional classification of wind waves and an even larger data set of W . Given that swell steepness values exceeded the critical value of Mitsuyasu and Yoshida [2005] of 0.01, the coastal location of MVCO could provide a suitable site at which to investigate the interaction of wind waves and opposing swell. In further field studies striving to verify the laboratory observations of swell wave/wind wave modulation, concurrent measurements of ocean wave spectra and W could provide an excellent representation of one of the possible sources of spectral energy flux, i.e., energy dissipation through wave breaking.…”

“…[40] Using the formulation of Mitsuyasu and Yoshida [2005], we found that typical values for swell wave steepness for the present study ranged between 0.002 and 0.026. This range of steepness values is similar to the range of steepness values of the long waves generated in the laboratory by Mitsuyasu and Yoshida [2005] and includes the critical steepness value of 0.01 noted above.…”

A review of wave climate and prediction along the Spanish Mediterranean coast

“…The second implication is related to momentum transfer, where many authors have highlighted that under mixed wave-train conditions the drag coefficient may increase appreciably. Additionally, Donelan (1987) and Mitsuyasu and Yoshida (1989) have shown a different wave growth rate in conditions of pre-existing swell. These conditions will produce errors on the predicted spectral shapes.…”