Seo, H., M. Jochum, R. Murtugudde, A. J. Miller and J. O. Roads, 2007:
Feedback of Tropical Instability Wave-induced atmospheric variability
onto the ocean.
Journal of Climate, 20, 5842-5855.
The effects of atmospheric feedbacks on tropical instability waves (TIWs) in the
equatorial Atlantic Ocean are examined using a regional high-resolution coupled climate
model. The analysis from a 6-year hindcast from 1999-2004 reveals a negative
correlation between TIW-induced wind perturbations and TIW-induced ocean currents,
which implies damping of the TIWs. On the other hand, the feedback effect from the
modification of Ekman pumping velocity by TIWs is small compared to the contribution
to TIW growth by baroclinic instability. Overall, the atmosphere reduces the growth of
TIWs by adjusting its wind response to the evolving TIWs. The analysis also shows that
including ocean current (mean + TIWs) in the wind stress parameterization reduces the
surface stress estimate by 15-20% over the region of the South Equatorial Current.
Moreover, TIW-induced perturbation ocean currents can significantly alter surface stress
estimations from scatterometers, especially at TIW frequencies. Lastly, the rectification
effect from the atmospheric response to TIWs on latent heat flux is small compared to the
mean latent heat flux.