Studies of the vertical structure of horizontal currents near Bermuda

A number of vertical profiles of horizontal motion at a site 70 km south of Bermuda were obtained in 1969 and 1970. An extensive analysis of the distribution of kinetic energy as a function of vertical mode was conducted. Rough equipartition of the kinetic energy into the barotropic (25 ergs/cm3) and lowest baroclinic (20 ergs/cm3) was found. This study was partly prompted by our concern as to whether conventional current measuring techniques, such as current meters and Swallow floats, can adequately resolve the low-frequency evolution of the vertical structure. There seems little doubt that the gross features of the two lowest modes can be monitored by sparse sampling in the vertical, but accurate estimates of their amplitudes may be difficult to obtain owing to aliasing by weak higher-order internal modes.