TITLE:
Impact of the Waves on the Sea Surface Roughness under Uniform Wind Conditions: Idealized Cases for Uniform Winds (Part I)
AUTHORS:
José Augusto P. Veiga, Mônica R. Queiroz
KEYWORDS:
Surface Gravity Waves, Wind Sea, Ocean Waves, Young Waves, Old Waves
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.5 No.3,
July
24,
2015
ABSTRACT: The
effect of the surface gravity waves over sea surface roughness length (z0) is investigated from
several idealized numerical experiments with the Wave-Watch-III (WW3) model.
The WW3 model is combined with a simplified model to estimate z0, CD, u* and U10 as function of the
sea state. The impacts related to the presence of the ocean waves over z0 are obtained from
conditions of growing (young waves) and mature seas (old waves). The wave
spectrum is obtained from WW3 model for each idealized simulation under uniform
wind conditions. Uniform wind experiments range from 15 to 45 m/s. The
simplified algorithm determines z0, CD, u* and U10 for cases of young waves, old waves and by the Charnock method. The results
show that when the ocean is characterized by young waves, both z0 and CD (drag coefficient) increase while U10 is reduced. In Charnock
case, the values of z0, CD and U10 have no dependence with the presence of gravity
waves. Experiments using winds higher than 30 m/s result in young waves’ CD values higher than the CD value for old waves. Even
for young waves CD values
are high for cases of strong winds. The results also show that in experiments
using winds higher than 30 m/s the dependence between CD and wave age becomes stronger, which is in accordance
with other studies.