ASA 126th Meeting Denver 1993 October 4-8

1pAO9. Arctic ambient noise and climate change.

Warren W. Denner

EOS Res. Associates, P. O. Box 1378, Carmel Valley, CA 93924

In global warming, sea ice plays a significant role, and sea ice conditions may provide one of the most sensitive parameters to monitor. Modeling predicts that warming will be greatest at high latitude, and sea ice properties are very sensitive to warming and changes in atmospheric forcing. Therefore, sea ice might provide a sensitive marker for climate change. The mechanical properties of sea ice are related to the ice temperature, salinity, thickness, concentration, and flow size distribution. It has been established that the ambient noise field under pack ice is correlated to the mechanical properties, ice conditions, and forcing. Many studies over the last two decades have delineated some of these relationships. The hypothesis of this paper is that monitoring the ambient noise under the ice, for which there is well-developed and reliable technology, may be an excellent way to detect a climate change signal. This paper will review the relationships between under ice ambient noise and the properties of the ice pack. Based on what is known, a monitoring system consisting of remotely operated buoys is proposed. A proposed buoy design and sampling array for the Arctic is presented. Used in conjunction with satellite remote sensing, the system could provide for continuous monitoring of the ice pack for other purposes and would be cost effective for acoustic monitoring of the climate change signal in the Arctic.