noaa-cave-19885 Borneo High Resolution Holocene Speleothem Oxygen Isotope Data Chen, S.; Hoffmann, S.S.; Lund, D.C.; Cobb, K.M.; Emile-Geay, J.; Adkins, J.F. Borneo High Resolution Holocene Speleothem Oxygen Isotope Data 2016-03-16 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/19885 Investigator S. Chen Investigator S.S. Hoffmann Investigator D.C. Lund Investigator K.M. Cobb Investigator J. Emile-Geay Investigator J.F. Adkins earth science paleoclimate speleothems depth,null,null,millimeter,null,speleothems,null,null,N,null earth science paleoclimate speleothems delta 18O,calcium carbonate,null,standard deviation unit,null,speleothems,filtered|interpolated,isotope ratio mass spectrometry,N,interpolated to 0.5-yr resolution and filtered with a 2–7 yr band wavelet filter developed from Torrence and Compo (1998). earth science paleoclimate speleothems age,null,null,calendar year before present,null,speleothems,null,null,N,null earth science paleoclimate speleothems delta 18O,calcium carbonate,null,per mil VPDB,null,speleothems,raw,isotope ratio mass spectrometry,N,null earth science paleoclimate speleothems carbon isotopes earth science paleoclimate speleothems oxygen isotopes geoscientificInformation ENSO 13548 cal yr BP -44 cal yr BP Complete 4.2587 4.2587 114.9649 114.9649 250 250 Ocean Indian Ocean Malaysia Bukit Assam Cave>LATITUDE 4.2587>LONGITUDE 114.9649 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 Sang Chen, Sharon S. Hoffmann, David C. Lund, Kim M. Cobb, Julien Emile-Geay, Jess F. Adkins 2016 Earth and Planetary Science Letters 442 61-71 10.1016/j.epsl.2016.02.050 http://www.sciencedirect.com/science/article/pii/S0012821X16300759

The El Nino-Southern Oscillation (ENSO) is the primary driver of interannual climate variability in the tropics and subtropics. Despite substantial progress in understanding ocean-atmosphere feedbacks that drive ENSO today, relatively little is known about its behavior on centennial and longer timescales. Paleoclimate records from lakes, corals, molluscs and deep-sea sediments generally suggest that ENSO variability was weaker during the mid-Holocene (4-6 kyrBP) than the late Holocene (0-4 kyrBP). However, discrepancies amongst the records preclude a clear timeline of Holocene ENSO evolution and therefore the attribution of ENSO variability to specific climate forcing mechanisms. Here we present d18O results from a U-Th dated speleothem in Malaysian Borneo sampled at sub-annual resolution. The d18O of Borneo rainfall is a robust proxy of regional convective intensity and precipitation amount, both of which are directly influenced by ENSO activity. Our estimates of stalagmite d18O variance at ENSO periods (2-7 yr) show a significant reduction in interannual variability during the mid-Holocene (3240-3380 and 5160-5230 yrBP) relative to both the late Holocene (2390-2590 yrBP) and early Holocene (6590-6730 yrBP). The Borneo results are therefore inconsistent with lacustrine records of ENSO from the eastern equatorial Pacific that show little or no ENSO variance during the early Holocene. Instead, our results support coral, mollusc and foraminiferal records from the central and eastern equatorial Pacific that show a mid-Holocene minimum in ENSO variance. Reduced mid-Holocene interannual d18O variability in Borneo coincides with an overall minimum in mean d18O from 3.5 to 5.5 kyrBP. Persistent warm pool convection would tend to enhance the Walker circulation during the mid-Holocene, which likely contributed to reduced ENSO variance during this period. This finding implies that both convective intensity and interannual variability in Borneo are driven by coupled air-sea dynamics that are sensitive to precessional insolation forcing. Isolating the exact mechanisms that drive long-term ENSO evolution will require additional high-resolution paleoclimatic reconstructions and further investigation of Holocene tropical climate evolution using coupled climate models. STUDY NOTES: Subannual oxygen isotope record in six Holocene time windows from stalagmite BA03, Bukit Assam Cave, Borneo, Malaysia, plus decadal average d18O and d13C

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/pacific/borneo2016ba03.txt Data File; Bukit Assam Cave Stalagmite BA03 High Resolution Holocene d18O Data GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/pacific/borneo2016ba03enso.txt Data File; Bukit Assam Cave Stalagmite BA03 ENSO-band d18O standard deviation GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/speleothem/pacific/borneo2016ba03decadal.txt Data File; Bukit Assam Cave Stalagmite BA03 Decadal Resolution d18O and d13C Data USA/NOAA DIF Version 9.8.4 2019-06-06 2019-06-06