Global ocean vertical velocity from a dynamically consistent ocean state estimate

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Liang, Xinfeng, Spall, Michael A., Wunsch, Carl
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley & Sons 2017
• Subjects: Vertical velocity; Vertical transport; Vertical exchange; Ocean state estimate; Climate change; Southern Ocean; Antarctic; The Antarctic; Antarc*
• Online Access: https://hdl.handle.net/1912/9414

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 8208–8224, doi:10.1002/2017JC012985. Estimates of the global ocean vertical velocities (Eulerian, eddy-induced, and residual) from a dynamically consistent and data-constrained ocean state estimate are presented and analyzed. Conventional patterns of vertical velocity, Ekman pumping, appear in the upper ocean, with topographic dominance at depth. Intense and vertically coherent upwelling and downwelling occur in the Southern Ocean, which are likely due to the interaction of the Antarctic Circumpolar Current and large-scale topographic features and are generally canceled out in the conventional zonally averaged results. These “elevators” at high latitudes connect the upper to the deep and abyssal oceans and working together with isopycnal mixing are likely a mechanism, in addition to the formation of deep and abyssal waters, for fast responses of the deep and abyssal oceans to the changing climate. Also, Eulerian and parameterized eddy-induced components are of opposite signs in numerous regions around the global ocean, particularly in the ocean interior away from surface and bottom. Nevertheless, residual vertical velocity is primarily determined by the Eulerian component, and related to winds and large-scale topographic features. The current estimates of vertical velocities can serve as a useful reference for investigating the vertical exchange of ocean properties and tracers, and its complex spatial structure ultimately permits regional tests of basic oceanographic concepts such as Sverdrup balance and coastal upwelling/downwelling. National Science Foundation Grant Numbers: OCE-1736633 , OCE-1534618 , OCE-0961713; National Oceanic and Atmospheric Administration Grant Number: NA10OAR4310135 2018-04-27