VERTICAL MOTIONS IN THE SOUTHERN OCEAN
Date
2025-05
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
Vertical motions (upwelling and downwelling) play an essential role in the
vertical transport of oceanic properties and materials. While past studies have reported
intense upwelling and downwelling in the Southern Ocean, a comprehensive analysis
dedicated to these vertical motions in the Southern Ocean remains to be accomplished.
Here, we analyze vertical velocity estimates in the Southern Ocean from the ocean
synthesis product ECCOv4, focusing on its spatial and temporal variability. We find a
general upwelling pattern from the Antarctic continent to around 55 °S and increasing
average vertical velocity estimates with increasing depth and near bathymetry features,
the Antarctic perimeter, and rough topography. Large temporal variations are observed
around the perimeter of the continent and near large bathymetric features (e.g., the
Campbell and Kerguelen Plateaus). Exploring links between interannual variations
and climate modes reveals a statistically significant moderate positive correlation
between vertical velocity and SAM from Antarctica to around 60 degrees S and a
negative correlation from 60 degrees S and northward. The results also show a
moderate negative correlation between the Niño3.4 Index and vertical velocity in most
of the Pacific sector of the Southern Ocean from Antarctica to 50 degrees with some
positive correlation northward of 50 degrees S. This study has implications that ENSO
and SAM could be anticorrelated and have opposing effects on vertical velocities in
the Southern Ocean. These results also confirm the connection between intense
vertical motions and topography. This paper builds on previous work by illustrating
how local dynamics in the Southern Ocean affect vertical motions and may have
implications for the climate system.