Ambient noise characteristics of the northwestern Barents Sea

Abstract

In support of the 1988–1989 CEAREX drift experiment three ANMET ambient noise buoys were inserted on ice floes in a triangular pattern approximately 120 km on a side about 200 km north of Svalbard in mid-September 1988. The buoys drifted southward passing to the east of Svalbard providing hourly measurements of the noise field from 5–4000 Hz for 2–4 months. Extensive environmental data were available with which to examine the effect of wind stress and ice motion on the noise field. The median spectra from these three buoys were quite similar with differences of about 3 dB being observed, the larger differences being at the higher frequencies where local noise effects dominate. The spectra were comparable to those found in the Eurasian Basin in winter. A 12-h periodicity was noted in both the noise and ice speed data, the result of forcing by tidal or inertial oscillations. A 52-h periodicity was noted at one buoy which lasted through the winter and was subjected to recurring synoptic scale storms. For frequencies below 100 Hz the temporal coherency was about 15 h. At low frequencies wind stress was the most important noise correlate, followed closely by ice speed. The noise field responded rapidly to the passage of storms generated by the Icelandic Low which migrated over the northern Barents Sea with the arrival of the noise peak being associated with the time of passage of the storm front past each buoy.