TITLE:
Impact of the Waves on the Sea Surface Roughness Length under Idealized Like-Hurricane Wind Conditions (Part II)
AUTHORS:
José Augusto P. Veiga, Mônica R. Queiroz
KEYWORDS:
Wave Prediction, Surface Gravity Waves, Hurricane Translation Speed
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.5 No.3,
July
24,
2015
ABSTRACT: In this
study the effect of the surface waves over sea surface roughness (z0) and drag coefficient (CD) is investigated by
combining an ocean wave model and a simplified algorithm, which estimates z0 and CD with and without dependence on the sea state. This
investigation was possible from several numerical simulations with the
Wave-Watch-III (WW3) model for complex wind conditions. The numerical
experiments were performed for idealized like-hurricanes with different
translation speed (0, 5 and 10 m/s) and maximum wind speed (MWS) at the centre
(35, 45 and 55 m/s). It is observed that z0 and CD are strongly
dependent on the sea state, via substantial modification in Charnock
parameterization (zch). As
the hurricane translation speed increases more discrepancies in z0 and CD are observed in opposite quadrants around the region
of MWS. As for instance, higher, longer and older (or more developed) waves,
located in the front-right quadrant, produce lower values of z0 and CD. In the rear-left quadrant, where the waves are
lower, shorter and younger (or less developed), higher values of z0 and CD are observed. In addition the difference between
values on opposite quadrants increases as the hurricane intensity increases,
showing the hurricane intensification dependence. Interesting aspects are
observed in scatter plotting wave age versus Charnock coefficient. It is also
observed that zch, which
has a constant value of 0.0185, is modified by the sea state, where young waves
produce higher values of zch,
while old waves are related to lower values of zch when compared with zch without dependence on sea state.