SOFAR floats for POLYMODE

The design of a neutrally buoyant float and associated tracking and support equipment developed for the POLYMODE experiment is described. Floats with a signaling range of 1500 Km and an endurance of 2-1/2 years signal via the deep sound channel to both land based receiving stations and moored, portable receivers. Recordings of float signals are collected and centrally processed, providing both daily positions and two-day averages of temperature and pressure measured at each float. Floats are equipped with both a simple, active controller to insure isobaric operation, and a relocation and recovery capability.