Fig. 5: Pacific zonal mean path densities.
From: Diffusion controls the ventilation of a Pacific Shadow Zone above abyssal overturning
Pacific zonal averages of the surface-to-interior path density (a–j) and of the interior-to-surface path density (k–t). (The path density is the dimensionless local fraction of water in origin-to-destination transit – see Methods.) Surface origin or destination regions as indicated in the titles and defined in Fig. 4a: Antarctic marginal seas (AMS), subpolar Southern Ocean (SP SO), low and mid latitudes (Low&Mid Lat), the northern Pacific (NPac), and the northern Atlantic (NAtl). The magenta outlines indicate the Pacific Shadow Zone (PSZ) or the Pacific Abyssal Zone (PAZ) and the part of the surface regions within the Pacific, while the cyan contours are Pacific zonal mean neutral density (−1000) in units of kg m−3. A generic feature of the A → B path density in the presence of diffusion is that is goes to zero close to A and close to B, where most water undergoes either A → A or B → B return trips72.
