A recent experiment conducted to test whether Arctic Ocean temperature change and sea ice thickness and roughness can be monitored using long-range, low-frequency acoustics was a resounding success. The Transarctic Acoustic Propagation (TAP) experiment, conducted in April 1994, showed that acoustic thermometry can be used to collect year-round data in this critical, sensitive part of the global climate system.

The oceanographic structure of the Arctic and the depth distribution of the acoustic modes make the Arctic especially suitable for acoustic thermometry. In fact, acoustic thermometry has many advantages for collecting climate data in the Arctic over satellite, icebreaker, or submarine. Longterm observations of the changes in acoustic phase, travel time, and amplitude of many transarctic paths could provide synoptic measurements of Arctic Ocean temperature and sea ice properties, particularly average ice thickness [Mikhalevsky et al., 1991]. Arctic Ocean temperature change is impossible to obtain with satellites, and synoptic longterm monitoring is difficult and expensive with ice breakers and submarines.