A one‐dimensional internal wave antenna was maintained in the main thermocline at Bermuda for 10 months. The antenna consists of three temperature sensors 1 km apart at a depth of about 600 meters plus engineering sensors. The signals are generally incoherent until periods approaching 12 hours are reached, when the sensors become coherent at zero phase. A large, variable, internal semidiurnal tide was measured. The diurnal tides appear to be generally absent, but there is an unexplained energy rise at periods of about 19 hours, which may be related to the inertial period at 22 hours. Much of the high‐frequency incoherence is ascribed to the presence of a strong local microstructure, possibly generated on the island itself.

A new moored instrument which makes repeated high vertical resolution profiles of current, temperature, and salinity in the upper ocean over extended periods was used to observe midwinter conditions near Bermuda. The operation and performance of the instrument, called the profiling current meter (PCM), in the surface wave environment of winter storms is reported here. The PCM profiles along the upper portion of a slightly subsurface mooring by adjusting its buoyancy under computer control. This design decouples the instrument from vertical motions of the mooring induced by surface waves, so that its electromagnetic current sensor operates in a favorable mean‐to‐fluctuating flow regime. Current, temperature, and electrical conductivity are (vector) averaged into contiguous preselected bins several meters wide over the possible profile range of 20‐ to 250‐m depth. The PCM is capable of collecting 1000–4000 profiles in a 6‐ to 12‐month period, depending on depth range and ambient currents. A variety of baroclinic motions are evident in the Bermuda observations. Upper ocean manifestations of both Kelvin and superinertial island‐trapped waves dominate longshore currents. Vertical coherences of onshore current and temperature suggest that internal wave vertical wave number energy distribution is independent of frequency but modified by island bathymetry. Kinetic energy in shear integrated over a 115.6‐m‐thick layer in the upper ocean is limited to values less than or equal to the potential energy required to mix the existing stratification. Mixing events occur when kinetic energy associated with shear drives the bulk Richardson number (defined by the ratio of energy integrals over the range profiled) to unity, where it remains while shear and stratification disappear together.

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A moored self‐recording instrument designed to measure the fine scale temperature and velocity vector variability of the ocean in a vertical plane containing the mean velocity vector is described. (Since the conception, design, and naming of the microscale sensing array (MSA) the scale designation of phenomenon with wave lengths in the range (0) 1 to (0) 10 m has been changed from ‘mieroscale’ to ‘fine scale.’) The structure holds 16 water velocity sensors (propellors) and 14 water temperature sensors (thermistors). These sensors are mounted along two vertical masts, each 8 m long, separated horizontally by a 20‐m spar. The whole structure is rigid, buoyed by two aluminum spheres, each 1 m in diameter, providing a net buoyancy for the instrument of about 386 kg. Contained within the spheres are an electronic data acquisition system, a magnetic tape recorder, primary batteries, a compass, and accelerometers to measure roll and pitch attitude. A separate cylindrical housing contains a pressure transducer and preamplifiers to sense depth. Provision is made to measure MSA translational motion by means of an acoustic transceiver and remote transponders. Instrument life is primarily dependent upon tape storage (53 million bits) and data sampling rate, which is easily preset to various continuous or burst modes. Maximum allowable operating depth is presently 900 m. The MSA has been deployed four times in the main thermocline southeast of Bermuda and once in the New England Continental Shelf bottom boundary layer.