University of Tasmania
Browse
Joyce2004jpo.pdf (1.42 MB)

Ocean response and feedback to the SST dipole in the Tropical Atlantic

Download (1.42 MB)
journal contribution
posted on 2023-05-16, 17:56 authored by Joyce, TM, Frankignoul, C, Yang, J, Helen PhillipsHelen Phillips
The equatorial SST dipole represents a mode of climate variability in the tropical Atlantic Ocean that is closely tied to cross-equatorial flow in the atmosphere, from the cold to the warm hemisphere. It has been suggested that this mode is sustained by a positive feedback of the tropical winds on the cross-equatorial SST gradient. The role, if any, of the tropical ocean is the focus of this investigation, which shows that at the latitudes of the SST signal (centered on 10°N/S) there is a weak positive feedback suggested in data from the last half century, that the cross-equatorial wind stress is closely coupled to this SST gradient on monthly time scales with no discernable lag, and that the period from January to June is the most active period for coupling. Northward (southward) anomalies of cross-equatorial wind stress are associated with a substantial negative (positive) wind stress curl. This wind system can thus drive a cross-equatorial Sverdrup transport in the ocean from the warm to the cold side of the equator (opposite the winds) with a temporal lag of only a few months. The oceanic observations of subsurface temperature anda numerical model hindcast also indicate a clear relationship between this mode of wind-driven variability and changes in the zonal transport of the North Equatorial Countercurrent. It is estimated that the time-dependent oceanic flow is capable of providing a significant contribution to the damping of the SST dipole but that external forcing is essential to sustaining the coupled variability. © 2004 American Meteorological Society.

History

Publication title

Journal of Physical Oceanography

Volume

34

Issue

11

Pagination

2525-2540

ISSN

0022-3670

Department/School

Institute for Marine and Antarctic Studies

Publisher

American Meteorological Society

Place of publication

Boston, USA

Repository Status

  • Restricted

Socio-economic Objectives

Climate variability (excl. social impacts)

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC