抄録
Acoustic digital data telemetry makes it possible to retrieve the observed values on a surface ship at any time during long-term underwater measurement. Several sea trials have been carried out totest feasibility and reliability of the telemetry by means of acoustic pulses from an ocean bottom heat flow meter newly developed for long-term measurement. More than 90% of values retrieved by the acoustic telemetry is in good agreement with ones memorized in the bottom equipment and recovered later. Bit length of each acoustic pulse for this data telemetry can be selected from 100msec to 10msec in accordance with the ambient acoustic noiselevel. Under normal sea states, 20msec is sufficient length of a pulse for the data retrieval from a depth of 6, 000 meters.
