In this project funded by The Swedish National Space Agency we track the ocean circulation in a series of Earth System Models and Satellite data. This project aims to study these exchanges from a so-called Lagrangian perspective, where one takes into account where a water mass comes from and where it is going. This is in contrast to the more traditional studies where one only looks at the changes locally without knowing either the origin or destination of the water (Eulerian perspective). However, the Lagrangian method requires some calculations based on data that either comes from our circulation models that are part of the climate models or from satellite observations. The Lagrangian method consists of calculating trajectories to precisely follow the water between different areas in the ocean and therefore places the ocean circulation in a larger perspective. Here we will use calculations from a trajectory model (TRACMASS) that Döös has developed over the years