The role of the South Pacific in modulating Tropical Pacific variability

Journal Article · Wed Dec 04 00:00:00 EST 2019 · Scientific Reports

DOI:https://doi.org/10.1038/s41598-019-52805-2· OSTI ID:1624505

Chung, Christine T. Y. ^[1]; Power, Scott B. ^[2]; Sullivan, Arnold ^[3]; Delage, François ^[2]

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1. Bureau of Meteorology (Australia); DOE/OSTI
2. Bureau of Meteorology (Australia)
3. Commonwealth Scientific and Industrial Research Organisation (CSIRO) (Australia)

Tropical Pacific variability (TPV) heavily influences global climate, but much is still unknown about its drivers. We examine the impact of South Pacific variability on the modes of TPV: the El Niño-Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO). We conduct idealised coupled experiments in which we suppress temperature and salinity variability at all oceanic levels in the South Pacific. This reduces decadal variability in the equatorial Pacific by ~30% and distorts the spatial pattern of the IPO. There is little change to overall interannual variability, however there is a decrease in the magnitude of the largest 5% of both El Niño and La Niña sea-surface temperature (SST) anomalies. Possible reasons for this include: (i) reduced decadal variability means that interannual SST variability is superposed onto a ‘flatter’ background signal, (ii) suppressing South Pacific variability leads to the alteration of coupled processes linking the South and equatorial Pacific. A small but significant mean state change arising from the imposed suppression may also contribute to the weakened extreme ENSO SST anomalies. The magnitude of both extreme El Niño and La Niña SST anomalies are reduced, and the associated spatial patterns of change of upper ocean heat content and wind stress anomalies are markedly different for both types of events.

• Research Organization: Utah State Univ., Logan, UT (United States)
• Sponsoring Organization: National Oceanic and Atmospheric Administration (NOAA); USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: SC0010687
• OSTI ID: 1624505
• Journal Information: Scientific Reports, Journal Name: Scientific Reports Journal Issue: 1 Vol. 9; ISSN 2045-2322
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
atmospheric dynamics
physical oceanography