Tom and Wenrui are co-authors on a manuscript called A Review of Green’s Function Methods for Tracer Timescales and Pathways in Ocean Models. The manuscript is submitted to JAMES and the preprint is here. Here’s some more information:

The global ocean circulation disperses trace substances, like dissolved chemicals, via currents and mixing. Characterizing the dispersion timescales and pathways is an essential goal of oceanography in order to reveal how distant parts of the ocean are connected, and how the ocean stores and releases trace substances. This paper reviews the concepts and theory behind tracer dispersion in the global ocean, focusing on a powerful diagnostic of tracer timescales and pathways called the tracer Green’s function. Practical examples of these diagnostics are presented, and practical implementation issues are discussed.