Equatorial Atlantic interannual variability: the role of heat content.

Ding, Hui, Keenlyside, Noel and Latif, Mojib (2010) Equatorial Atlantic interannual variability: the role of heat content. Open Access Journal of Geophysical Research: Atmospheres, 115 . C09020. DOI 10.1029/2010JC006304.

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The dynamics of the Equatorial Atlantic zonal mode are studied using observed sea surface height (SSH), sea surface temperature (SST), and heat flux and reanalysis wind stress and upper ocean temperature. Principal oscillation pattern (POP) analysis shows that the zonal mode is an oscillatory normal-mode of the observed coupled system, obeying the delayed-action/recharge oscillator paradigm for ENSO. Variations in equatorial averaged SSH, a proxy for upper ocean heat content, precede SST anomalies in the cold tongue by 4-5 months, about a quarter of the POP period. Positive subsurface temperature anomalies appear in the west, as a delayed response to the preceding
cold event. These propagate eastward, where due to the shallow thermocline they can influence SST, leading to the next warm event. Although SST variations exhibit weak westward propagation during some zonal mode events,
POP analysis indicates that to first order there is no zonal propagation in SST. Net surface heat flux anomalies generally act to damp SST anomalies.
The zonal mode explains a large amount (70%) of SST variability in the east and a significant fraction (19%) of equatorial variability. Thus, the predictability
potential in the Equatorial Atlantic on seasonal time scales may be considerably higher than currently thought.

Document Type: Article
Keywords: Oceanography; Climatology; Equatorial Atlantic zonal mode; climate variability; atmosphere-ocean interaction
Research affiliation: OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > SFB 754
OceanRep > SFB 754 > A1
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union)
Projects: SFB754, Future Ocean
Date Deposited: 04 Aug 2010 10:20
Last Modified: 23 Sep 2019 18:02
URI: https://oceanrep.geomar.de/id/eprint/8742

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