Maiana Atoll Isotope (delta 18O, delta 13C) Data for 1840 to 1995

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Maiana Atoll Isotope (delta 18O, delta 13C) Data for 1840 to 1995
Maiana bimonthly oxygen isotopic composition, 1840-1995. Notes on the data: File includes columns for Year AD (bimonthly resolution = dec/jan, feb/mar) and coral d18O. The coral used in this study grew (and still does grow) at Maiana Atoll, Republic of Kiribati (1N, 173E). The colony lies at a depth of ~6m (low tide) and is about 4m in height. Annual growth rate is roughly 11mm/yr. Methods: Sampling and isotopic analysis: Cores (8.5 cm diameter) drilled from living coral colonies were slabbed and X-rayed to identify annual density bands and optimal sampling transects. Samples were drilled along the growth axis continuously at 1mm resolution. Stable isotopic analysis (d18O and d13C) of powdered samples was performed on a Micromass Optima with Isocarb automated preparation system at the University of Colorado's Institute for Arctic and Alpine Research. Analytical precision is =&oacute;&oacute;0.08 d18O and =&oacute;&oacute;0.05 d13C. The Maiana record is continuous except for a gap from 1901-1905, which we bridged through straight forward comparison and splicing of data from a coral record from nearby Tarawa Atoll. Age model: Seasonally varying d13C values and ephemeral annual density bands provide the basis for annual age assignment. Ages were adjusted subseasonally by comparison to major El Ni&oacute;&oacute;o and La Ni&oacute;&oacute;a anomalies in a regional rainfall index (available at <>); this procedure allows us to align major peaks and troughs that occur within the same calendar year with adjustments that are generally less than 3 months. Because corals grow at variable rates throughout the year, these small chronological adjustments are reasonable and customary (and do not affect estimates of multi-year variability). Near the base of the core, an age adjustment of 1 year was needed, suggesting an age uncertainty on the full record of &oacute;&oacute;1 year. The Maiana coral grew at a rate of 7-12 mm per year; we interpolated records to a common time step of bimonthly resolution for further analysis. Replication: The record from core MAI95-2-3 is well replicated by additional records of 65-70 years from Maiana and Aranuka, ~75 km southeast of Maiana, (JEC, FEU, and JTO, manuscript in preparation) and by a published 97-year record from Tarawa Atoll, ~30 km north of Maiana. Correlation coefficients among coral and instrumental data over the common period 1950-89 are consistently high (Maiana_correlations.txt), adding confidence to single-core reconstruction of regional variability in western Kiribati. We focus on the MAI95-2-3 record for further analysis because it extends the record of ENSO into pre-instrumental periods and avoids nonstationarity that may be introduced through inclusion of records that differ in length. The 4-coral average correlates slightly better with instrumental data than most individual coral records, but only Mai 2-3 extends the instrumental record of ENSO. Linear correlation coefficients demonstrate a strong agreement between the Maiana record and ENSO variability (Table 1), and decadalaverages of the Maiana record correlate significantly over the past century (>95% confidence) with those from the Tarawa coral record and regional rainfall indices, substantiating the reality of these more subtle low-frequency signals (JEC, FEU, and JTO, manuscript in preparation).
  1. How should this data set be cited?

    Urban, Frank, Cole, Julia, and Overpeck, Jonathan, 200010, Maiana Atoll Isotope (delta 18O, delta 13C) Data for 1840 to 1995: World Data Center for Paleoclimatology Data Contribution Series 2000-063, World Data Center for Paleoclimatology, Boulder, Boulder.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: 173
    East_Bounding_Coordinate: 173
    North_Bounding_Coordinate: 1
    South_Bounding_Coordinate: 1

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  4. Does the data set describe conditions during a particular time period?

    Ending_Date: 1995
    Currentness_Reference: Publication Date

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  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

    2. What coordinate system is used to represent geographic features?

  7. How does the data set describe geographic features?

    coral variable
    coral variable (Source: coral variable)

    delta 18O (per mil) (Source: Craig, H., 1957. Isotopic standards for mass spectrometric analysis of carbon dioxide. Geochimica Cosmochimica Acta, 12:113-140)

    Range of values
    Units:per mil

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Urban, F.E., J. E. Cole, and J.T. Overpeck, 2000, Influence of mean climate change on climate variability from a 155-year tropical Pacific coral record. Nature 407, 989-993.

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Paleoclimatic Research

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Access_Constraints: None
Use_Constraints: Please cite original reference when using this data.

  1. Who distributes the data set? (Distributor 1 of 1)

    NOAA Paleoclimatology Program
    Data Manager
    325 Broadway, Code E/CC23
    Boulder, Colorado 80305-3328

    (303) 497-6280 (voice)
    (303) 497-6513 (FAX)

    Hours_of_Service: 9-5 MST Monday-Friday
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    Other Documents

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    Disclaimer- While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

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Last modified: 24-Jan-2017
Last Reviewed: 31-Mar-2011
Metadata author:
NOAA Paleoclimatology Program
Data Manager
325 Broadway, Code E/CC23
Boulder, Colorado 80305-3328

(303) 497-6280 (voice)
(303) 497-6513 (FAX)

Hours_of_Service: 9-5 MST Monday-Friday
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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