Parametrization of gas transfer velocities and sea-state-dependent wave breaking

Tellus B ◽  
2005 ◽  
Vol 57 (2) ◽  
pp. 87-94 ◽  
Author(s):  
DAVID K. WOOLF
Keyword(s):  
Wave Breaking ◽  
Gas Transfer ◽  
Sea State ◽  
State Dependent

scholarly journals Laboratory investigation of crest height statistics in intermediate water depths

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190183 ◽  
Author(s):  
I. Karmpadakis ◽  
C. Swan ◽  
M. Christou
Keyword(s):  
Water Depth ◽  
Wave Breaking ◽  
Field Data ◽  
Full Range ◽  
Second Order ◽  
Intermediate Water ◽  
Sea State ◽  
Nonlinear Amplification ◽  
Effective Water ◽  
Water Depths

This paper concerns the statistical distribution of the crest heights associated with surface waves in intermediate water depths. The results of a new laboratory study are presented in which data generated in different experimental facilities are used to establish departures from commonly applied statistical distributions. Specifically, the effects of varying sea-state steepness, effective water depth and directional spread are investigated. Following an extensive validation of the experimental data, including direct comparisons to available field data, it is shown that the nonlinear amplification of crest heights above second-order theory observed in steep deep water sea states is equally appropriate to intermediate water depths. These nonlinear amplifications increase with the sea-state steepness and reduce with the directional spread. While the latter effect is undoubtedly important, the present data confirm that significant amplifications above second order (5–10%) are observed for realistic directional spreads. This is consistent with available field data. With further increases in the sea-state steepness, the dissipative effects of wave breaking act to reduce these nonlinear amplifications. While the competing mechanisms of nonlinear amplification and wave breaking are relevant to a full range of water depths, the relative importance of wave breaking increases as the effective water depth reduces.

scholarly journals Wind Speed and Sea State Dependencies of Air‐Sea Gas Transfer: Results From the High Wind Speed Gas Exchange Study (HiWinGS)

2017 ◽  
Vol 122 (10) ◽  
pp. 8034-8062 ◽  
Author(s):  
B. W. Blomquist ◽  
S. E. Brumer ◽  
C. W. Fairall ◽  
B. J. Huebert ◽  
C. J. Zappa ◽  
...  
Keyword(s):  
Wind Speed ◽  
Gas Exchange ◽  
Gas Transfer ◽  
High Wind ◽  
Sea State ◽  
High Wind Speed ◽  
Exchange Study

scholarly journals First air–sea gas exchange laboratory study at hurricane wind speeds

2013 ◽  
Vol 10 (6) ◽  
pp. 1971-1996
Author(s):  
K. E. Krall ◽  
B. Jähne
Keyword(s):  
Wave Breaking ◽  
High Speed ◽  
Wind Wave ◽  
Breaking Waves ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Wind Speeds ◽  
Hurricane Wind ◽  
Wide Range ◽  
Enhanced Surface

Abstract. In a pilot study conducted in October and November 2011, air–sea gas transfer velocities of the two sparingly soluble trace gases hexafluorobenzene and 1,4-difluorobenzene were measured in the unique High-Speed Wind-Wave Tank at Kyoto University, Japan. This air–sea interaction facility is capable of producing hurricane strength wind speeds of up to u10=67 m s−1. This constitutes the first lab study of gas transfer at such high wind speeds. The measured transfer velocities k600 spanned two orders of magnitude, lying between 11 cm h−1 and 1180 cm h−1 with the latter being the highest ever measured wind induced gas transfer velocity. The measured gas transfer velocities are in agreement with the only available dataset at hurricane wind speeds (McNeil and D'Asaro, 2007). The disproportionately large increase of the transfer velocities found at highest wind speeds indicates a new regime of air–sea gas transfer, which is characterized by strong wave breaking, enhanced turbulence and bubble cloud entrainment. It was found that tracers spanning a wide range of solubilities and diffusivities are needed to separate the effects of enhanced surface area and turbulence due to breaking waves from the effects of bubble and spray mediated gas transfer.

Distribution of Crest Amplitudes in Severe Seas With Breaking

1993 ◽  
Vol 115 (1) ◽  
pp. 9-15 ◽  
Author(s):  
D. L. Kriebel ◽  
T. H. Dawson
Keyword(s):  
Theoretical Model ◽  
Probability Distribution ◽  
Wave Breaking ◽  
Laboratory Data ◽  
Selective Reduction ◽  
Wave Crest ◽  
Wave Spectra ◽  
Sea State ◽  
Subsequent Modification ◽  
Nonlinear Increase

A theoretical model is presented for the probability distribution of wave crest amplitudes in severe seas states with wave breaking. As the severity of a sea state increases, nonlinearities cause an increase in the amplitudes of the largest wave crests with a subsequent modification of the distribution of wave crest amplitudes from the linear Rayleigh theory. In this paper, a theory for the probabilities of these nonlinear crest amplitudes is first reviewed based on earlier work. The further limitations on these nonlinear crest amplitudes by wave breaking are then considered. As a result, a theoretical model is presented to account for both: 1) the nonlinear increase in the highest wave crests, and 2) the selective reduction of some fraction of these high crests due to wave breaking. This model is then verified using several sets of laboratory data for severe breaking seas having approximate JONSWAP wave spectra.

On wave breaking and the equilibrium spectrum of wind-generated waves

1969 ◽  
Vol 310 (1501) ◽  
pp. 151-159 ◽  
Keyword(s):  
Drag Coefficient ◽  
Wave Breaking ◽  
Low Frequency ◽  
Spectral Density Function ◽  
Sea Surface ◽  
Sea State ◽  
Wave Cycle ◽  
Equilibrium Spectrum ◽  
Special Case ◽  
Made In

A theoretical calculation is made of the loss of energy by wave breaking in a random sea state in terms of the spectral density function. In the special case of the equilibrium spectrum F(σ) = αg 2 σ -5 the proportion ɷ of energy lost per mean wave cycle is found to be given by ω ≑ e -1/8α irrespective of the low-frequency cut-off in the spectrum. Assuming that in the equilibrium state the loss of energy by breaking is comparable to that supplied by the wind, one can estimate the constant α in terms of the drag coefficient of the wind on the sea surface. It is found that α≑ -1/8/ln[1600C 3/2 ( ρ air/ ρ water)]. Taking a representative value of C one finds α ≑ 1.3 x 10 -2 , which falls within the range of observed values of α. The above equation for α is rather insensitive to the various assumptions made in the analysis. There is some evidence, derived from observation, that α may not in fact be quite constant, but may decrease slightly as the wave age ( gt/U ) or the non-dimensional fetch ( gx/U 2 ) is increased. It is suggested that the drag coefficient may behave similarly.

Sign in / Sign up

Export Citation Format

Share Document