This project is a component of the Tropical Instability Wave Experiment (TIWE). The P.I. will collaborate with other TIWE investigators to study the vorticity balance of the upper ocean near the crests of the Pacific tropical instability waves and the thermohaline fine structure of the front separating cold equatorial water from warmer water to the north. A depth- cycled CTD and an Acoustic Doppler Profiler will be used to sample the temperature, salinity, and velocity fields, in conjunction with deployment of an array of satellite-tracked drifted and a thermistor chain.