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A weak El Niño/Southern Oscillation with delayed seasonal growth around 4,300 years ago
Citation
McGregor, HV and Fischer, MJ and Gagan, MK and Fink, D and Phipps, SJ and Wong, H and Woodroffe, CD, A weak El Nino/Southern Oscillation with delayed seasonal growth around 4,300 years ago, Nature Geoscience, 6 pp. 949-953. ISSN 1752-0894 (2013) [Refereed Article]
Copyright Statement
Copyright 2013 Macmillan Publishers Limited
DOI: doi:10.1038/NGEO1936
Abstract
Earth’s interannual climate variability is dominated by El
Niño/Southern Oscillation (ENSO). Palaeoclimate records
indicate a lower ENSO variance during the middle Holocene
compared with today; however, model simulations have not
reproduced the full magnitude of the changes, and whether
external forcing drives large intrinsic ENSO variability
is therefore a matter of considerable debate. Here we
present a 175-year-long, monthly resolved oxygen isotope
record, obtained from a Porites coral microatoll located on
Kiritimati (Christmas) Island, in the NINO3.4 region of the
central equatorial Pacific. Our quantitative record of ENSO
variability about 4,300 years ago shows that ENSO variance
was persistently reduced by 79%, compared with today,
and it exhibits a dominant annual cycle. Season-specific
analysis shows that El Niño events were damped during their
September–November growth phase, and delayed relative to
the climatological year. We suggest that the higher boreal
summer insolation at the time strengthened the tropical Pacific
zonal winds as well as the gradients in sea surface temperature,
and thereby led to an enhanced annual cycle and suppressed
ENSO. As the weak ENSO is subject to interdecadal amplitude
modulation, we conclude that amplitude modulation is likely to
remain robust under altered climates. Our findings show that
ENSO is capable of responding to external forcing.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | palaeoclimate, El Nino-Southern Oscillation, Holocene, corals, isotopes, Kiribati |
| Research Division: | Earth Sciences |
| Research Group: | Physical geography and environmental geoscience |
| Research Field: | Palaeoclimatology |
| Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
| Objective Group: | Understanding climate change |
| Objective Field: | Climate variability (excl. social impacts) |
| UTAS Author: | Phipps, SJ (Dr Steven Phipps) |
| ID Code: | 104728 |
| Year Published: | 2013 |
| Web of Science® Times Cited: | 80 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2015-11-18 |
| Last Modified: | 2017-10-30 |
| Downloads: | 0 |
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