Zonal Momentum Balance at the Equator

Abstract

Coll. Oceanogr., Oregon State Univ., Oceanogr. Adm. Build. 104, Corvallis, OR 97331-5503, USA J (Journal-Article) M (Marine) Turbulent kinetic energy dissipation rates measured at 140 degree W during the TROPIC HEAT I experiment and a production rate-dissipation rate balance argument have been used to calculate the zonal turbulent stress at 30 to 90 m depth. The calculated turbulent stress at 30 m depth amounts to only 20% of the wind stress, and decreases exponentially with depth below 30 m. It is concluded that either 1) the measured estimates of dissipation rate are too small, 2) the actual large-scale zonal pressure gradient, mesoscale eddy flux, and advection during the observation period were highly atypical and had a very shallow depth scale, 3) some process other than the simple diffusion of momentum through shear instabilities is transporting the momentum, or 4) the assumption of a production-dissipation balance in the turb...