Energy dissipation across the wave spectrum - Breaking and Dissipation of Ocean Surface Waves - page 274

Figure 7.11 Same as in Figure 7.9 , but for ratio of φ i ( 2 f p ,θ) and φ p ( 2 f p ,θ) directional spectra
of Figure 7.10 at double peak frequency 2 f p . Figure is reproduced from Young & Babanin ( 2006a )
© American Meteorological Society. Reprinted with permission
due to wave breaking, and the breaking has usually been regarded as a poorly understood
and basically unknown phenomenon, formulations of the term have often been loosely
based on physics and served as a residual tuning knob. The tradition was laid by Komen
et al. ( 1984 ), who calibrated the dissipation and other source terms together, based on
their joint contribution to the integral-wave-growth curves which were the only reliable
experimental knowledge at the time, and the approach persisted throughout more than 20
years. Such significant attempts of the past years to improve the S ds parameterisation as
Polnikov ( 1991 ), Young & Banner ( 1992 ), Banner & Young ( 1994 ), Tolman & Chalikov
( 1996 ), Alves & Banner ( 2003 ), Rogers et al. ( 2003 ) and Bidlot et al. ( 2007 ), among
others, rested firmly within this tradition. More recent studies by Ardhuin et al. ( 2007 )
and Van der Westhuysen et al. ( 2007 ), which both highlighted some serious limitations of
this approach and resulted in updates of operational wave-forecast models, are still, to an
extent, based on the residual tuning. And it is only now that the newly devised dissipa-
tion functions and their calibration appeal directly to the recently found and/or understood
physics of breaking and dissipation, including its threshold behaviour and cumulative
effects ( Babanin et al. , 2007d , 2010c ; Tsagareli , 2009 ; Ardhuin et al. , 2010 ). Babanin et al.
( 2007d , 2010c ), Tsagareli ( 2009 ) and Tsagareli et al. ( 2010 ) went further and suggested