noaa-coral-14968 Kiritimati Island 4.3ka Fossil Coral d18O Data McGregor, H.V.; Fischer, M.J.; Gagan, M.K.; Fink, D.; Phipps, S.J.; Wong, H.; Woodroffe, C.D. Kiritimati Island 4.3ka Fossil Coral d18O Data 2013-09-06 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/14968 Investigator H.V. McGregor Investigator M.J. Fischer Investigator M.K. Gagan Investigator D. Fink Investigator S.J. Phipps Investigator H. Wong Investigator C.D. Woodroffe earth science paleoclimate corals and sclerosponges delta 18O,Porites sp.,95% confidence interval margin of error,per mil VPDB,null,corals and sclerosponges,composited|interpolated,isotope ratio mass spectrometry,N,null earth science paleoclimate corals and sclerosponges strontium/calcium,Porites sp.,null,millimole per mole,null,corals and sclerosponges,interpolated,inductively-coupled plasma atomic emission spectroscopy,N,null earth science paleoclimate corals and sclerosponges age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,null earth science paleoclimate corals and sclerosponges number of samples,null,null,count,null,corals and sclerosponges,null,null,N,null earth science paleoclimate climate reconstructions|corals and sclerosponges age,null,null,year,null,climate reconstructions|corals and sclerosponges,null,null,N,null earth science paleoclimate corals and sclerosponges delta 18O,Porites sp.,null,per mil VPDB,null,corals and sclerosponges,composited|interpolated,isotope ratio mass spectrometry,N,null earth science paleoclimate corals and sclerosponges delta 18O,Porites sp.,null,per mil VPDB,null,corals and sclerosponges,anomalized|composited|detrended|interpolated,isotope ratio mass spectrometry,N,anomalized to mean annual cycle; detrended over length of record earth science paleoclimate climate reconstructions|corals and sclerosponges sea surface temperature,strontium/calcium,null,degree Celsius,monthly,climate reconstructions|corals and sclerosponges,null,null,N,null earth science paleoclimate corals and sclerosponges oxygen isotopes geoscientificInformation ENSO 4400 cal yr BP 4200 cal yr BP Complete 2 2 -157.3 -157.3 -9 -9 Ocean Pacific Ocean Central Pacific Ocean Kiribati Kiritimati Island>LATITUDE 2>LONGITUDE -157.3 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII H. V. McGregor, M. J. Fischer, M. K. Gagan, D. Fink, S. J. Phipps, H. Wong, and C. D. Woodroffe 2013 Nature Geoscience 6 11 949-953 10.1038/ngeo1936 http://www.nature.com/ngeo/journal/v6/n11/abs/ngeo1936.html

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. STUDY NOTES: Data files updated 5/2/2014 to include Sr/Ca, Sr/Ca-SST, and Dd18O data from fossil coral XM35 and modern coral XM22, as plotted in Supplementary Figure 9, McGregor et al. 2013 Nature Geoscience. Fossil coral oxygen isotope (d18O) data, and fossil and modern coral Sr/Ca data from near Kiritimati Island, eastern tropical Pacific. Living and fossil Porites sp. microatolls were collected at Kiritimati Island (1°50'N, 157°25'W). The well-preserved fossil coral (XM35) grew continuously for 175 years between ~4.2 and ~4.4 kyBP, as indicated by an average U-series age of 4,243 ± 9 years BP, and by clear annual d18O cycles and density bands. Skeletal d18O was measured in fossil coral XM35 at approximately monthly resolution. The age model for coral XM35 was established in the same way as for the modern coral microatoll record (XM22; McGregor et al. 2011), by assigning d18O maxima to early February. The d18O data were interpolated to give 12 values/year. The overall age model uncertainty for the coral time-series is estimated as ± 1 year. For comparison a compilation of Kiritimati Island modern coral d18O records (modern coral d18O stack; Evans et al., 1998; Woodroffe et al., 2003; McGregor et al., 2011), spanning March 1938 to May 2007 was constructed. Comparisons of the annual cycle were made using a sub-set of the modern coral d18O stack (WM_stack; Woodroffe et al., 2003; McGregor et al., 2011) modern coral d18O record for the period February 1978 to May 2007. Time series were broken down into Trend, Annual, and Residual (interannual) components, which occupy distinct spectral bins. Statistical analyses were performed on these components (Supplementary Methods). Coral XM35, age: ~4.3 kyBP, location: Kiritimati Island (01°44.212'N, 157°12.522'W). Coral Sr/Ca was measured on the youngest 30 years of coral microatoll XM35 (coral years 147-177), and for 1994-2007 in modern coral microatoll XM22 to verify the dominant contribution of SST to Kiritimati coral d18O in non-El Nino years. The within-run precision was +/- 0.02 mmol/mol (0.2% RSD).

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/kiritimati2013.xls GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/kiritimati2013.txt USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11