Revisiting the cause of the eastern equatorial Atlantic cold event in 2009

Kristin Burmeister, Peter Brandt, Joke F. Lübbecke

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
3 Downloads (Pure)

Abstract

An extreme cold sea surface temperature event occurred in the Atlantic cold tongue region in boreal summer 2009. It was preceded by a strong negative Atlantic meridional mode event associated with north-westerly wind anomalies along the equator from March to May. Although classical equatorial wave dynamics suggest that westerly wind anomalies should be followed by a warming in the eastern equatorial Atlantic, an abrupt cooling took place. In the literature two mechanisms—meridional advection of subsurface temperature anomalies and planetary wave reflection—are discussed as potential causes of such an event. Here, for the first time we use in situ measurements in addition to satellite and reanalysis products to investigate the contribution of both mechanisms to the 2009 cold event. Our results suggest that meridional advection is less important in cold events than in corresponding warm events, and, in particular, did not cause the 2009 cold event. Argo float data confirm previous findings that planetary wave reflection contributed to the onset of the 2009 cold event. Additionally, our analysis suggests that higher baroclinic modes were involved.
Original languageEnglish
Pages (from-to)4777-4789
Number of pages13
JournalJournal of Geophysical Research: Oceans
Volume121
Issue number7
DOIs
Publication statusPublished - 13 Jun 2016

Keywords

  • Atlantic cold tongue
  • Atlantic meridional mode
  • Atlantic zonal mode
  • meridional advection
  • planetary wave reflection

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