Equatorial entrainment zone simulations

Abstract

The equatorial entrainment zone model of Garwood et al. (1989) is employed along with data collected by Moum et al. (1984) during the Tropic Heat I Experiment to explain how the dissipation of turbulence is related to surface forcing of wind stress and net heat flux. Four numerical experiments with different atmospheric conditions are conducted with the entrainment zone model. Solar radiation is diurnally repeated, and wind stress is held constant in the first case. The model is forced with linearly varied wind speed in the second case and uses observed winds for the third cases. The first three cases demonstrated the effects of wind stress on the dissipation of turbulence. In the final case both observed wind and observed solar radiation were applied to the model to simulate the effect of realistic forcing, allowing a comparison between model-predicted and observed values of dissipation. Numerical solutions qualitatively agree with the observations, and the time and depth dependence of the diurnal dissipation cycle are well reproduced by the model.