Control of decadal and bidecadal climate variability in the tropical pacific by the off-equatorial South Pacific Ocean

Hiroaki Tatebe, Yukiko Imada, Masato Mori, Masahide Kimoto, Hiroyasu Hasumi

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Delayed negative feedback processes determining intrinsic decadal and bidecadal time scales for the tropical variability in the Pacific are investigated based on climate model experiments. By comparing a control run driven by preindustrial forcing and partial blocking runs driven by the same forcing but with ocean temperature and salinity restored to climatology in selected regions, subsurface oceanic signals of South Pacific origin are shown to precede SST variability in the Ni~no-3.4 region. Using a linear reduced-gravity ocean model driven only by wind stress changes and an offline tracer model, oceanic wave adjustment triggered by changes of wind stress curl in the South Pacific extratropics is suggested to be essential for the decadal component of the equatorial SST, while slower isopycnal advection of subsurface temperature anomalies from the formation region of South Pacific Eastern Subtropical Mode Water controls the bidecadal component. The intrinsic time scales of the tropical variability are regulated by simple linear ocean dynamics.

Original languageEnglish
Pages (from-to)6524-6534
Number of pages11
JournalJournal of Climate
Volume26
Issue number17
DOIs
Publication statusPublished - 2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

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