| It has been suggested in older and recent literature (e.g. Shaffer et al., 2004) that a broad deep eastern boundary flow is linking the equatorial Pacific Ocean to the Southern Ocean. The depth range of this flow corresponds to the Pacific Deep Water (2500m) where it is suggested by the distribution of primordial 3He originating from the East Pacific Rise. In this study, we propose to use a large set of data along with inverse techniques to estimate the stationary advection and diffusion of water properties and tracer concentrations (potential vorticity, potential temperature, salinity, dissolved oxygen and silica concentration) in the area of interest. The various data are combined into an new inverse model first developed by McKeague et al. (2005), Herbei et al. (2006). The model uses a forward advection-diffusion model and Markov Chain Monte-Carlo techniques to give estimates of velocities along and across surfaces of neutral density as well as isopycnal diffusivities. It is composed of 9 layers between the 27.4 and 28 neutral densities. The circulation in the upper layers of the model compares well with direct independent estimates of velocities from subsurface oat trajectories (WOCE and Argo). We investigate the water exchange in the deeper layers in regards to the 3He distribution along the Eastern boundary and its mixing with the Antarctic Circumpolar Current. The model is able to estimate vertically dependent rates of oxygen utilization as well as lateral eddy diffusivities of tracers. |
