Michael V. Greening
Jasco Res. Ltd., 9865 W. Saanich Rd., Sidney, BC V8L 3S1, Canada
Pierre Zakarauskas
Defence Research Establishment Pacific
Short-term Arctic ambient noise spectra over the frequency band 2--200 Hz are presented along with a two-component noise model capable of reproducing these spectra. The model is based on the measured source spectrum and the spatial, temporal, and source level distributions of both active pressure ridging and ice cracking. Modeled ambient noise levels are determined by summing the input energy of the distributions of ice cracking and pressure ridging events and removing the propagation loss. Both modeled and measured spectra show that below 40 Hz, the ambient noise is dominated by a single or few active pressure ridges at ranges of tens of kilometers. Above 40 Hz, the ambient noise is dominated by a large distribution of thermal ice-cracking events with over 50% of the total noise level produced by events within 6-km range and over 80% produced by events within 30-km range.