An analysis of acoustic propagation across the East Greenland Frontal Zone

Abstract

Oceanographic data (CTD and XBT profiles) were obtained in the summer of 1983 on a transect from within the marginal sea ice zone (at about 76° 30′ N Lat) across the northern Greenland and Norwegian Seas to Tromsø, Norway. The initial 150‐km section embraces the complex frontal zone between waters of polar origins in the upper layer of the East Greenland Current and Arctic waters of the Greenland Sea gyre. Interposed between these two water types is a warmer, more saline water of Atlantic origin. The data from this 150‐km section have been used as input for an environmental range‐dependent sound propagation model (GRASS). By independently limiting the number of bottom bounces and refractive turning points, insight is gained into the contribution of each principal propagation mode: bottom bounce, surface duct, and convergence zone for various source and receiver depths. The relative importance of each propagation mode to the total propagation loss is presented as a function of range from the East Greenland Current end of the section. [Work supported by ONR and NUSC.]