EFFECTS OF SEA-ICE COVER ON ACOUSTIC RAY TRAVEL-TIMES, WITH APPLICATIONS TO THE GREENLAND SEA TOMOGRAPHY EXPERIMENT

The travel-time effects of a sea ice cover on an acoustic pulse are es timated using generalized ray theory. This expands upon the previous w ork done by Jin and Wadhams [Prog. Oceanogr. 22, 249-275 (1989)] by in cluding the effects of frequency dispersion and different sets of ice parameters. Travel-time changes due to single reflections are approxim ated by plane wave reflection theory, and compared to the generalized ray theory results. Statistical effects for multiple reflections, such as the ice thickness probability distribution function, Fresnel zone averaging, and shadowing are considered. Finally, the effects of ice-i nduced travel-time changes on tomographic inversions for water column oceanography are considered. The implications of this work on the 1988 -89 Greenland Sea tomography experiment are considered in detail.