Barrier layers in the tropical Atlantic Ocean: Growth and decay mechanisms and impact of Amazon river runoff

Abstract

In this thesis the freshwater changes and the underlying processes in the northern tropical and subtropical Atlantic Ocean are investigated by analyzing daily outputs of high-resolution eddy-resolving numerical simulations of the Atlantic Ocean using MITgcm. The impacts of small-scale ocean processes like eddies and fronts embedded in the regional circulation, on the evolution of barrier layers i.e. stratification in the upper-ocean are investigated. The growth and decay mechanisms of the barrier layers in the tropical Atlantic Ocean are identified and quantified. Moreover, with numerical sensitivity experiments, I explore the impacts of extreme and realistic changes in the Amazon river discharge on the northern tropical Atlantic ocean circulation and upper-ocean barrier layers.