Deep Circulation in the Eastern Chile Basin
A deep southward current off the coast of Chile has been observed in several past studies from hydrography, tracers and an inverse model. The current is thought be centered between 2500 - 3400 m and contribute to the transport of deep water from low to higher latitudes. This affects the Southern Ocean water characteristics and potential vorticity, yet this current is not represented in high resolution global climate models. Existing hydrographic data from e.g. the CLIVAR section P6 and the Southern Ocean State Estimate (SOSE) show the location of the current directly above the Peru - Chile Trench, visible in existing hydrography as well as direct measurements of velocity. Instantaneous speeds recorded from LADCP data are up to 15 cm/s. Using available hydrographic data we investigate the origin and fate of this current that brings low-oxygen and low-pv water from the west towards the coast. In the south the current interacts with the Chilean Ridge. We investigate potential seasonality and interannual variability as well as possible driving mechanisms.