NSF Award
9619180
Acoustic and physical data collected in the Arctic since 1990 indicates a strengthening in the front between Atlantic/Pacific waters from near the Lomonosov Ridge toward the Alpha/Mendeleyev Ridge when compared with data from the 1970's and 1980's. Despite the key role Arctic processes play in global climate change our knowledge of Arctic water mass structure is still based on sparsely sampled measurements. The SCICEX program offers the scientific community the unique and unprecedented opportunity to use simple under ice, submarine launched, expendable CTD (U/I SSXCTD) measurements to nearly double the number of high quality transarctic oceanographic survey sections. Complementing the submarine CTD data contribution to understanding Arctic circulation are acoustic measurements of ocean temperature, salinity and ice roughness which offer the capability to synoptically detect majop ocean circulation shifts. The Arctic Climate Observations using Underwater Sound (ACOUS) program will begin recording year round ocean temperature changes, and sea ice thickness and extent, along fixed acoustic paths in 1997. Submarine sampling provides accurate local measurements of temperature, salinity and ice cover, whereas the advantage of basin scale acoustic measurements is synoptic observation of the basin integrated circulation effects. The Transarctic Acoustic Propagation (TAP) experiment demonstrated the feasibility of acoustics as a tool to monitor major movements of fronts. The scientific objectives of using submarine CTD and ice profile data from SCICEX-97 are to: (1) establish an historical record of temperature and salinity from the Beaufort Sea to the Barents Sea to monitor global circulation changes and validate Arctic Ocean circulation models, (2) use the measured data to 'tune' the ACOUS acoustic thermometer, and (3) provide temperature, salinity and ice draft measurements concurrent with acoustic emissions.
