Dynamics of eastern boundary currents and their effects on sound speed structure

Abstract

Identifying the influence of eastern boundary current (EBC) dynamical processes on sound speed structure can provide better ocean models for acoustic predictions in littoral regions. This study will explore the effects of currents, wind and eddies on the sound speed structure of two different EBC models, the North Canary Current System (NCCS) and the Leeuwin Current System (LCS). These systems represent classical features of EBCs as well as regional anomalies. This study seeks to introduce sound speed analysis to the sigma coordinate primitive equation models and determine which regions of EBCs experience the largest changes in sound speed and most intense gradients. Results of model runs show that the dynamics of EBCs lead to large changes in sound speed and distort the vertical sound speed profile. The greatest change in sound speed in either region is caused by upwelling in the NCCS. Surface and associated subsurface eddies in the LCS are the largest scale feature in the study. The undercurrent of the NCCS and Meddies present the most intense (horizontal and vertical) gradients of sound speed change.