The East Pacific Rise current: Topographic enhancement of the interior flow in the South Pacific Ocean

• Main Authors: Zilberman, NV, Roemmich, DH, Gille, ST
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2017
• Subjects: Oceanography; Earth Sciences; Engineering; Fluid Mechanics and Thermal Engineering; Geophysics; Meridional circulation; ocean interior; Sverdrup balance; Argo data; topographic steering; East Pacific Rise; Meteorology & Atmospheric Sciences; Antarctic; Pacific; Antarc*
• Online Access: https://escholarship.org/uc/item/2ws1g1dc

Abstract: Observations of absolute velocity based on Argo float profiles and trajectories in the ocean interior show evidence for an equatorward current, the East Pacific Rise current, between 42°S and 30°S, along the western flank of the East Pacific Rise. The East Pacific Rise current carries predominantly intermediate water masses, including Subantarctic Mode Water and Antarctic Intermediate Water, and deeper waters, from the southern edge of the subtropical gyre toward the Equator. The 2004 to 2014 mean East Pacific Rise current transport extrapolated through the 0–2600m depth range is 8.1±1.6 sverdrup (Sv) (1 Sv=106m3s−1), consistent with a wind‐driven interior transport influenced by the East Pacific Rise topography. While deep ocean mixing and geothermal heating can both create pressure gradients that support geostrophic flows in the deep ocean, this study indicates that about half of the East Pacific Rise current transport is associated with topographic steering of the deep flow over the East Pacific Rise.