ASA 127th Meeting M.I.T. 1994 June 6-10

2pUW11. The frontal effect in ATOC.

E. C. Shang

Y. Y. Wang

CIRES, University of Colorado/NOAA/Environmental Technology Laboratory, Boulder, CO 80303

Acoustic propagation along the Hawaii--Aleutain path of ATOC has been investigated based upon two ocean models: (1) Levitus annual mean data on a 1-deg grid and (2) Semtner--Charvin's model of one realization (Feb.) with 1/2-deg resolution. The adiabaticity has been evaluated by using four indicators: (a) adiabatic travel time discrepancy, (b) modal repopulation, (c) modal dispersion, and (d) mode-coupling matrix. It is found that significant mode coupling takes place at the sub-Arctic front area (N-44.8(degrees)) in Semtner--Charvin's model but not in Levitus model because Semtner--Charvin's model gives a much stronger double channel at that area than Levitus data. [Work supported by ARPA and NOAA.]