High Pacific native Guilderson

Core/Site name:

Nauru Island

Country/Region:

Pacific

Elevation:

-14

Archive:

corals

Species:

Porites

Proxy measurement:

radiocarbon

Sampling resolution:

monthly

Startyear:

1947 AD

Endyear:

1995 AD

All uncertainties:

+/- 4 per mil, based on analyses of an in-house homogenized, near modern coral sample. The data are age corrected (Stuiver & Polach, 1977).

Description:

We have generated a high resolution coral Δ14C record spanning the last 50 years to document the seasonal and interannual redistribution of surface waters in the western tropical Pacific. Prebomb (1947–1956) Δ14C values average −63‰ and have a total range of 30‰. Values begin to increase in 1957, reaching a maximum of 137‰ in mid-1983. Large interannual variability of up to 80‰ closely follows the El Niño-Southern Oscillation (ENSO). During each ENSO warm phase, Δ14C values begin to increase, reflecting the reduction of low-14C water upwelling in the east and the invasion of subtropical water into the western equatorial tropical Pacific. Maximum Δ14C values are in phase or lag the corresponding sea surface temperature maxima in the eastern tropical Pacific, whereas the rapid return to more negative Δ14C is in phase with eastern Pacific ENSO indices. The highest-amplitude excursions occur during the 1965/1966 and 1972/1973 events, when the 14C contrast is highest between the eastern Pacific and subtropics. The 1982/1983 El Niño, although a larger ENSO event, has a lower Δ14C amplitude, reflecting the penetration of bomb radiocarbon into the equatorial undercurrent and the reduced contrast in Δ14C between thermocline and subtropical surface waters at that time. This coral record demonstrates the potential for using similar radiocarbon time series for documenting variability in Pacific shallow circulation over interannual and decadal timescales.

Data entered by name:

Ally May

Data entered by email:

This email address is being protected from spambots. You need JavaScript enabled to view it.

Main reference(s):

Guilderson, T.P., D.P. Schrag, M. Kashgarian, and J. Southon. 1998.Radiocarbon variability in the western equatorial Pacific inferred from a high-resolution coral record from Nauru Island. Journal of Geophysical Research

Link to reference 1:

http://www.agu.org/journals/jc/v103/iC11/98JC02271/

Data storage link 1:

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/coral/west_pacific/readme_nauru14c.txt

Data storage link 2:

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/coral/west_pacific/nauru14c.txt

Comments:

Entry updated by A. Wagner (This email address is being protected from spambots. You need JavaScript enabled to view it.) on 2/17/2012

Current dating method:

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Annual snow acc rate:

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Category: Ocean2k