Advective Time Scales of Agulhas Leakage to the North Atlantic in Surface Drifter Observations and the 3D OFES Model

Abstract

AbstractThe advective transit time of temperature–salinity anomalies from the Agulhas region to the regions of deep convection in the North Atlantic Ocean is an important time scale in climate, because it has been linked to variability in the Atlantic meridional overturning circulation. Studying this transit time scale is difficult, because most observational and high-resolution model data are too short for assessment of the global circulation on decadal to centennial time scales. Here, results are presented from a technique to obtain thousands of “supertrajectories” of any required length using a Monte Carlo simulation. These supertrajectories allow analysis of the circulation patterns and time scales based on Lagrangian data: in this case, observational surface drifter trajectories from the Global Drifter Program and Lagrangian data from the high-resolution OGCM for the Earth Simulator (OFES). The observational supertrajectories can only be used to study the two-dimensional (2D) surface flow, whereas th...