Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
Achievements and a Potential Role of Underwater Acoustics in Studying Large-Scale Changes in the Arctic Ocean
Alexander N. Gavrilov1, Peter N. Mikhalevsky2, Valerii V. Goncharov3, Yuri A. Chepurin4
1Centre for Marine Science & Technology, Curtin University of Technology, GPO Box U1987, Perth, 6845, Australia, Phone 61-8-9266-4696 , Fax 61-8-9266-4799, A.Gavrilov@cmst.curtin.edu.au
2Ocean Science and Technology, Science Applications International Corporation, 1710 SAIC Dr., McLean, VA, 22102, USA, Phone 703-676-4784, Fax 703-243-0643, peter@osg.saic.com
3Acoustic Waves Propagation Laboratory, P.P.Shirshov Institute of Oceanology, 36 Nakhimovskii pr., Moscow, 117851, Russia, Phone 7-095-129-1936, Fax 7-095-124-8943, gvv@rav.sio.rssi.ru
4Acoustic Waves Propagation Laboratory, P.P.Shirshov Institute of Oceanology, 36 Nakhimovskii pr., Moscow, Russia, Phone 7-095-129-1936, Fax 7-095-124-8943, chep@rav.sio.rssi.ru
The Transarctic Acoustic Propagation experiment in 1994 revealed integral, basin-scale warming of the Atlantic intermediate water layer relative to climatology, which supported the earlier observations of warming in this layer in certain regions of the Arctic Ocean. Both experimental and modeling results have shown that the travel time of individual modes of a low-frequency acoustic signal is a precise indicator of changes in the integral Atlantic water temperature along cross-Arctic sections.
The first long-term stationary system of Arctic acoustic thermometry was experimentally tested for 14 months in 1998-1999 in the framework of the Arctic Climate Observations using Underwater Sound program. Remote acoustic observations on the cross-Arctic path from Franz Josef Land to the Lincoln Sea detected substantial warming of Atlantic waters and a shoaling of the thermocline that occurred rapidly in the central Nansen Basin (83 - 840 N, 20 - 300 E) in the last quarter of 1999. Neither in-situ oceanographic measurements conducted in the adjacent regions in 1998 and later nor the ocean circulation models predicted such changes. The long-term acoustic transmissions in 1998-1999 were also capable of detecting seasonal variations of the mean thickness of sea ice along the cross-Arctic path.
At present, an extensive network of acoustic thermometry paths for multiyear observations in the Arctic Ocean is projected. The feasibility of acoustic halinometry, i.e. remote observations of salinity change in the upper layer, is also examined by numerical modeling.
Abstract Categories: Changes in the Sea
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