Long term very low frequency ambient noise: A window to the ocean and atmosphere

Long term time series data of ambient noise in deep water from a site near Wake Island in the western Pacific provide a window into processes occurring in the ocean and in the atmosphere. Acoustic noise data in the Very Low and Ultra Low Frequency bands show strong frequency components at major tidal frequencies, are correlated with El Niño Sea Surface Temperature Anomaly time records, and correlate also with yearly wind fluctuations. Directional ambient noise data also allow tracking of distant storms. Noise at 1 Hz was chosen in particular for study because the noise sources are primarily environmental and, thus, the data may serve as a harbinger of pending environmental change.