HEARD ISLAND FEASIBILITY TEST - ANALYSIS OF PACIFIC PATH DATA OBTAINED WITH A HORIZONTAL LINE ARRAY

Preliminary results from the Heard Island Feasibility Test are presented for data obtained with a towed horizontal line array off the coast of southern California. Signal characteristics examined include signal-to-noise ratios, sound-pressure levels, transmission loss, and arrival bearing angles. For the transmissions analyzed to date the mean sound-pressure level was found to be (63.8+/-2) dB//1 mu Pa. The mean transmission loss was found to be (150+/-3) dB which is significantly greater than that found for receivers in the Atlantic at similar ranges. The mean arrival angle was found to be (214+/-3)degrees T and a travel time of approximately 3 h 17 m was measured. Measurements compare favorably with model predictions which indicate that the relatively large transmission loss is due to bottom interactions in the south western Pacific.