An Interdecadal Shift of the Extratropical Teleconnection From the Tropical Pacific During Boreal Summer

Christopher H. O'Reilly, Tim Woollings, Laure Zanna, Antje Weisheimer

Research output: Contribution to journalArticle

Abstract

©2019. American Geophysical Union. All Rights Reserved. The extratropical teleconnection from the tropical Pacific in boreal summer exhibits a significant shift over the past 70 years. Cyclonic circulation anomalies over the North Atlantic and Eurasia associated with El Niño in the later period (1978–2014) are absent in the earlier period (1948–1977). An initialized atmospheric model ensemble, performed with prescribed sea surface temperature (SST) boundary conditions, replicates some key features of the shift in the teleconnection, providing clear evidence that this shift is not simply due to internal atmospheric variability or random sampling. Additional ensemble simulations, one with detrended tropical SSTs and another with constant external forcing are analyzed. In the model, the teleconnection shift is associated with climatological atmospheric circulation changes, which are substantially reduced in the simulation with detrended tropical SSTs. These results demonstrate that the climatological atmospheric circulation and associated teleconnection changes are largely forced by tropical SST trends.
Original languageEnglish (US)
Pages (from-to)13379-13388
Number of pages10
JournalGeophysical Research Letters
Volume46
Issue number22
DOIs
StatePublished - Nov 28 2019

Keywords

  • climate dynamics
  • decadal variability
  • El Niño–Southern Oscillation
  • ocean-atmosphere coupling
  • summer
  • teleconnections

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