Fig. 1. Arctic multi-year sea ice area: winter 1978-98.
Acoustical techniques, which have been tested in other oceans, offer a new and promising method for long-term monitoring in the Arctic. During a pilot Transarctic Acoustic Propagation experiment (TAP) conducted by Mikhalevsky in the spring of 1994, long range propagation (2600 km) in the Arctic Basin was performed. This experiment showed that transmission across the Arctic basin is possible. Furthermore, the results of this experiment show that the travel time and phase measurements are more than accurate enough to pick up changes caused by climate change in the Arctic basin (Mikhalevsky et al. 1999). By comparing simulated historical and present travel times to travel times measured during the TAP experiment, it is found a clear increase in travel time. This corresponds to the observed increase of the ocean temperature found in the oceanographic data.
