Glacial/interglacial changes in the East Australian current

H. C. Bostock*, B. N. Opdyke, M. K. Gagan, A. E. Kiss, L. K. Fifield

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    71 Citations (Scopus)

    Abstract

    The East Australian Current (EAC) is the western boundary current of the south Pacific gyre transporting warm tropical waters to higher southern latitudes. Recent modelling shows that the partial separation of the EAC (∼32°S) and the coupled formation of the Tasman Front (∼34°S) are caused by a steep gradient in the zonally integrated wind stress curl. Analysis of oxygen isotope ratios (δ18 O) in the planktonic foraminifer, Globigerinoides ruber, from sediment cores from the Coral Sea and Tasman Sea indicates that the EAC separation shifted northward to between 23 and 26°S during the last glacial. We suggest these results indicate a significant change in the Pacific wind stress curl during the glacial. Given recent evidence for El Niño-like conditions in the Pacific during the last glacial, with a reduction in the east-west sea surface temperature (SST) gradient, we suggest that weaker trade winds combined with more northerly, stronger westerlies were associated with a change to the wind stress curl, which repositioned the EAC separation and Tasman Front. In contrast, by ∼11 ka BP, the EAC separation was forced south of 26°S. This southward shift was synchronous with a rapid warming of tropical SSTs, and the onset of a La Niña-like SST configuration across the tropical Pacific. It appears that the south Pacific trade winds strengthened accordingly, causing the EAC to readjust its flow. This readjustment of the EAC marks the onset of modern surface-ocean circulation in the southwest Pacific, but the present EAC transport was only achieved in the late Holocene, after 5 ka BP.

    Original languageEnglish
    Pages (from-to)645-659
    Number of pages15
    JournalClimate Dynamics
    Volume26
    Issue number6
    DOIs
    Publication statusPublished - May 2006

    Fingerprint

    Dive into the research topics of 'Glacial/interglacial changes in the East Australian current'. Together they form a unique fingerprint.

    Cite this