TIDES AND BOTTOM CURRENTS OFF THE COAST OF NORTHERN CALIFORNIA 1

Tidal heights and current speed and direction 1 m above the sea floor, at a depth of 3,903 m, were measured for 43 days off the coast of northern California. From spectral analysis, the amplitudes and phases of 5 tidal components were estimated for tidal heights and eastern and northern components of velocity. For the M 2 component, the tidal height was found to be 48.1 cm; the east velocity 1.67 cm/sec, the north velocity 0.94 cm/sec; and the respective phases 277.4, 246.3, and 65.5 degrees. The observed currents were smaller than those predicted from the frictionless equations of motion. Frictional equations of motion were solved for v , the kinematic coefficient of viscosity, by equating observed and theoretical velocities for several models of rotating basins. v ranged between 0.78 and 5.24 cm 2 /sec for the M 2 component for the various models. None of the simple frictional models used was adequate to explain completely all of the data. The dissipation of energy for the M 2 component was calculated from v and ranged over an order of magnitude (from 2.05 to 17.06 × 10 − 2 ergs/cm 2 sec) for the several models used.