  Sutherland and Melville (2015a) investigated the relative contributions to
the total dissipation rate in the ocean surface wave boundary layer of
different breaking wave scales, from large-scale whitecaps to micro-breakers.
Based on their measurements of geometric/kinematic properties of breaking waves
for a wide range of wave ages, they inferred the dissipation rates from
breaking as a function of scale. These results were compared with their
complementary measurements of the total dissipation rate in the underlying wave
boundary layer. They reported that the total depth-integrated dissipation rate
in the water column agreed well with dissipation rate from breaking waves for
young to very old wind seas. They also reported high observed levels of
dissipation rate very near the sea surface. They concluded that this showed a
large fraction of the total dissipation rate was due to non-air entraining
micro-breakers and very small whitecaps. Because of its fundamental importance,
both physically and for accurate air-sea interaction modeling, we assess the
validity of these conclusions. Our analysis of their data shows that the
microbreakers and small whitecaps do not make a significant contribution to the
total turbulent dissipation rate in the wave boundary layer.
