Kauai Beacon receptions and analysis with open-access hydrophones in the North Pacific Ocean

Abstract

The Kauai Beacon began regularly transmitting a 75 Hz, maximum length sequence encoded, signal that has been received by hydrophones as far as 4000 km from the source. The received signal, which has travelled across the entire ocean basin, contains integrated environmental information about the full path between the transmitter and the receiver. This allows us to simultaneously understand how the environment effects long-range acoustic propagation, and to use the long-range acoustic propagation to estimate environmental variables such as path-averaged ocean temperature. In this talk, we present continued work to analyze the receptions of the Kauai Beacon using open-access ambient sound data recorded in the North Pacific Ocean. We present long-term trends of acoustic arrival times, the spread of the acoustic energy, and frequency shift of the signal due to mooring motion, or ocean state fluctuation. [Work supported by ONR.]