Atlantic Equatorial Undercurrent and associated cold tongue variability.

Hormann, Verena and Brandt, Peter (2007) Atlantic Equatorial Undercurrent and associated cold tongue variability. Open Access Journal of Geophysical Research: Oceans, 112 . C06017. DOI 10.1029/2006JC003931.

[thumbnail of jgrc10525-sup-0001-t01.txt] Text
jgrc10525-sup-0001-t01.txt - Supplemental Material

Download (85B)
[thumbnail of jgrc10525-sup-0002-t02.txt] Text
jgrc10525-sup-0002-t02.txt - Supplemental Material

Download (85B)
[thumbnail of Hormann_Brandt.pdf]
Preview
Text
Hormann_Brandt.pdf - Published Version

Download (2MB) | Preview

Supplementary data:

Abstract

The Atlantic Equatorial Undercurrent (EUC) is studied using a simulation for the period 1990–2002 with a high-resolution ocean general circulation model. Simulated transports of the EUC that supplies the annual mean upwelling in the central and eastern equatorial Atlantic are in good agreement with new transport estimates derived from ship observations, i.e., 19.9 and 14.0 Sv at 35°W and 23°W, respectively. Although the observations are not conclusive concerning the seasonal cycle of EUC transports, the simulated seasonal cycles fit largely in the observed range. The analysis of the EUC variability associated with interannual boreal summer variability of the equatorial cold tongue showed that cold tongue indices, defined either by near-surface temperature or steric height anomalies, are anticorrelated with thermocline EUC transport anomalies: A strong EUC corresponds to low near-surface temperatures and steric heights. The importance of equatorial waves for the cold tongue region is shown: Surface layer transport anomalies at 23°W and 10°W are significantly correlated with both near-surface temperature and steric height anomalies in the equatorial and coastal upwelling regions, indicating an associated eastward phase propagation along the equator toward the African coast where the signal bifurcates into two poleward branches along the coast and is reflected into a westward propagating wave.

Document Type: Article
Keywords: Oceanography; variability, equatorial Atlantic; ocean circulation
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union)
Projects: Future Ocean, AMMA
Expeditions/Models/Experiments:
Date Deposited: 03 Dec 2008 16:51
Last Modified: 07 Mar 2022 13:41
URI: https://oceanrep.geomar.de/id/eprint/4896

Actions (login required)

View Item View Item