Correlated Signals and Causal Transport in Ocean Circulation

This presentation introduces a method for obtaining causal transit time distributions from functions of time-lagged correlation in stochastically forced advective-diffusive transport equations. Two approaches to estimating oceanic transit times are (1) applying lagged correlation functions to oceanic signals such as temperature and salinity times series, and (2) interpreting Green's function solutions to transport equations as TTDs and estimating them from passive tracer concentrations. This presentation shows the equivalence of the time-correlation and Green's function approaches in a stochastically forced transport systems. The method is validated using low dimensional numerical models, including a box model of a Meridional Overturning Circulation, and then used to estimate transit times in the Denmark Strait Overflow.