| SPELEOTHEMS |
Rasbury and Aharon 2006 Avaiki Cave, Niue Island Stalagmite Layer Thickness Data
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Rasbury, M.;Aharon, P.A. 2006 ENSO-controlled rainfall variability records archived in tropical stalagmites from the mid-ocean
island of Niue, South Pacific. Geochem. Geophys. Geosyst. Vol. 7, Q07010
| Data Coverage |
North: -19 * South: -19 |
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West: -169.83 * East: -169.83 |
Start Year: 1760 AD
End Year: 2001 AD
Data: Please Cite Data Contributors!
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Summary: Niue Island is located in close proximity to the epicenter of the
South Pacific Convergence Zone (SPCZ), and its rainfall variability
is controlled by changes in the phase of the El Nino-Southern Oscillation
(ENSO) phenomenon. Four actively growing stalagmites displaying couplets
of light and dark calcite layers were sampled from a flank-margin cave
on Niue Island in order to determine the dominant climate factor
controlling lamina thickness and establish the usefulness of the
stalagmites as archives of ENSO variability records. Couplets counting,
AMS radiocarbon assays, and growth rates analysis (mean growth rate:
0.34 ± 0.04 mm/yr for n = 604) support the premise that these couplets
are annually deposited and their stalagmites contain records of up to
two centuries long. Comparison of band thickness records with instrumental
records of air temperature and rainfall kept on the island since 1930 and
1906,respectively, suggests that rainfall variability is the dominant
controlling factor. Coherency between the spectral power of the annual
layers unraveling periodicities at 2.4 and 5.4 years and that of annual
and monsoon rainfall at 2.4¿2.7 and 5.2 years corroborates the rainfall
control on the band thickness variability of the Niuean stalagmites.
Phase lags and amplitude discrepancies between rainfall and stalagmite
records are attributed to the impact of torrential rains accompanying
cyclones that occasionally struck the island. The excellent agreement
between the periodicities prominent in the Niuean stalagmites and those
typical of the ENSO phenomenon (2.4 and 4.3¿6.0 years) suggests the
latter exerts a dominant control on the stalagmite growth rates via
rainfall variability. Interdecadal periodicities at 10, 14, and 30 years
contained in the Niuean stalagmites spectral power are tentatively
attributed to ENSO phase changes driven by the Inter-Decadal Pacific
Oscillation (IPO). The Niuean stalagmites, exhibiting relative fast
growth rates and prominent layered sequences, hold promise to provide
continuous century to millennium-long high resolution atmospheric
records of ENSO history that will complement and expand the sea surface
temperature records archived in tropical Pacific corals.
More Info on Speleothems |
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Complete XML Record: noaa-cave-5442
(Last Revised: 2007-10-18 )
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