48
Setting the right hand sides of Eqs. (3.98) and (3.99) equal to each other results in Eq. (3.97).
At first glance it may appear unusual that the same expression for the dissipation
coefficient results for the case of currents as for the case of no currents. This can be
explained in part by the fact that Dailys work was with waves where breaking was depth
limited. For the case of current limited breaking (for example a stopping current), another
expression is necessary. In this study Eq. (3.97) will be used, since in general the current
field will be moderately weak. Such an assumption of weak currents was invoked in the
derivation of the governing parabolic equation.