# Palmyra Atoll Coral Sr/Ca Data 1909-1995 CE
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#               World Data Service for Paleoclimatology, Boulder
#                                   and
#                      NOAA Paleoclimatology Program
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# Template Version 4.0
# Encoding: UTF-8
# NOTE: Please cite original publication, NOAA Landing Page URL, dataset and publication DOIs (where available), and date accessed when using downloaded data.
# If there is no publication information, please cite investigator, study title, NOAA Landing Page URL, and date accessed.
#
# Description/Documentation lines begin with '#' followed by a space
# Data lines have no '#'
#
# NOAA_Landing_Page: https://www.ncei.noaa.gov/access/paleo-search/study/35381
#   Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata.
#
# Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-coral-35381.json
#   Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata.
#
# Data_Type: Corals and Sclerosponges
#
# Dataset_DOI: 10.25921/g725-gn95
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# Science_Keywords: 
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# Resource_Links
#
# Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/coral/central_pacific/sayani2022/sayani2022-pm1-srca.txt
#   Data_Download_Description: NOAA Template File; PM1 Sr/Ca Data
#
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# Contribution_Date
#   Date: 2022-01-20
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# File_Last_Modified_Date
#   Date: 2022-01-20
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# Title
#   Study_Name: Palmyra Atoll Coral Sr/Ca Data 1909-1995 CE
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# Investigators
#   Investigators: Sayani, H.R.; Cobb, K.M.; Monteleone, B.; Bridges, H.
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# Description_Notes_and_Keywords
#   Description: 
#---------------------------------------
# Publication
#   Authors: Sayani, H.R., K.M. Cobb, B. Monteleone, and H. Bridges
#   Published_Date_or_Year: 2022-09-01
#   Published_Title: Accuracy and reproducibility of coral Sr/Ca SIMS timeseries in modern and fossil corals
#   Journal_Name: Geochemistry, Geophysics, Geosystems
#   Volume: 23
#   Edition: 
#   Issue: 9
#   Pages: 
#   Report_Number: e2021GC010068
#   DOI: 10.1029/2021GC010068
#   Online_Resource: 
#   Full_Citation: 
#   Abstract: Coral strontium-to-calcium ratios (Sr/Ca) provide quantitative estimates of past sea surface temperatures (SST) that allow for the reconstruction of changes in the mean state and climate variations, such as the El Nino-Southern Oscillation, through time. However, coral Sr/Ca ratios are highly susceptible to diagenesis, which can impart artifacts of 1–2°C that are typically on par with the tropical climate signals of interest. Microscale sampling via Secondary Ion Mass Spectrometry (SIMS) for the sampling of primary skeletal material in altered fossil corals, providing much-needed checks on fossil coral Sr/Ca-based paleotemperature estimates. In this study, we employ a set modern and fossil corals from Palmyra Atoll, in the central tropical Pacific, to quantify the accuracy and reproducibility of SIMS Sr/Ca analyses relative to bulk Sr/Ca analyses. In three overlapping modern coral samples, we reproduce bulk Sr/Ca estimates within ±0.3% (1σ). We demonstrate high fidelity between 3-month smoothed SIMS coral Sr/Ca timeseries and SST (R = −0.5 to −0.8; p < 0.5). For lightly-altered sections of a young fossil coral from the early-20th century, SIMS Sr/Ca timeseries reproduce bulk Sr/Ca timeseries, in line with our results from modern corals. Across a moderately-altered section of the same fossil coral, where diagenesis yields bulk Sr/Ca estimates that are 0.6 mmol too high (roughly equivalent to −6°C artifacts in SST), SIMS Sr/Ca timeseries track instrumental SST timeseries. We conclude that 3–4 SIMS analyses per month of coral growth can provide a much-needed quantitative check on the accuracy of fossil coral Sr/Ca-derived estimates of paleotemperature, even in moderately altered samples.
#---------------------------------------
# Publication
#   Authors: Sayani, H.R., Cobb, K.M., DeLong, K., Hitt, N.T., and Druffel, E.R.M. 
#   Published_Date_or_Year: 2019
#   Published_Title: Intercolony d18O and Sr/Ca variability among Porites spp. corals at Palmyra Atoll: Toward more robust coral-based estimates of climate
#   Journal_Name: Geochemistry,Geophysics, Geosystems
#   Volume: 20
#   Edition: 
#   Issue: 11
#   Pages: 5270–5284
#   Report_Number: 
#   DOI: 10.1029/2019GC008420
#   Online_Resource: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GC008420
#   Full_Citation: 
#   Abstract: Quantitative estimates of natural climate variability are required to detect anthropogenic climate trends in the tropical Pacific; however, instrumental records from this region are too short and scarce. Coral oxygen isotopic (d18O) and strontium to calcium (Sr/Ca) records are often used to extend instrumental observations; however, differences in the mean Sr/Ca and d18O values of Porites spp. colonies from the same reef can introduce large uncertainties in coral-based climate reconstructions. To quantify intercolony variability at Palmyra Atoll, we generate monthly resolved Sr/Ca and d18O time series from five Porites spp. colonies that grew between 1980 and 2010. Monthly to interannual variability in Sr/Ca and d18O is well-reproduced among different colonies; however, we document intercolony offsets in mean Sr/Ca of ±0.09 mmol/mol (1s) or ~1 °C, and in mean d18O of ±0.12‰ (1s) or ~0.1 °C. The sensitivity of each proxy to climate also varies across colonies, with Sr/Ca-SST slopes ranging from -0.06 to -0.1 mmol mol-1 °C-1 and d18O-SST slopes ranging from -0.25 to -0.35‰ °C-1. Intercolony variability in both coral Sr/Ca and d18O reduces the reproducibility of coral-based d18Osw reconstructions across overlapping colonies. Accounting for both intercolony variability and slope error suggests that SST reconstructions using Sr/Ca from a single Palmyra coral have an uncertainty of ±1.3 °C (1s); however, replicating Sr/Ca records across multiple colonies can greatly reduce this uncertainty. A composite Sr/Ca record built using five modern cores, for example, offers a reduced error of ±0.6 °C (1s) in mean SST reconstructions, ~2.5 times smaller than errors associated with reconstructions from single corals.
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# Funding_Agency
#   Funding_Agency_Name: 
#   Grant: 
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# Site_Information
#   Site_Name: Palmyra Atoll PM1
#   Location: Ocean>Pacific Ocean>Central Pacific Ocean 
#   Northernmost_Latitude: 5.878
#   Southernmost_Latitude: 5.878
#   Easternmost_Longitude: -162.142
#   Westernmost_Longitude: -162.142
#   Elevation_m: 
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# Data_Collection
#   Collection_Name: PM1 Sr/Ca Sayani2022
#   First_Year: 1986
#   Last_Year: 1995
#   Time_Unit: year Common Era
#   Core_Length_m: 
#   Parameter_Keywords: trace metals
#   Notes: This dataset contains SIMS coral Sr/Ca data from a Porites sp. coral from Palmyra (core PM1).
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# Chronology_Information 
# Chronology: 
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# Variables
# PaST_Thesaurus_Download_Resource: https://www.ncei.noaa.gov/access/paleo-search/skos/past-thesaurus.rdf
#   PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format.
#
# Data variables follow that are preceded by "##" in columns one and two.
# Variables list, one per line, shortname-tab-var components: what, material, error, units, seasonality, data type, detail, method, C or N for Character or Numeric data)
#
## age	age,,,year Common Era,,corals and sclerosponges,,,N,
## Sr/Ca	strontium/calcium,Porites sp.,,millimole per mole,,corals and sclerosponges,,secondary ion mass spectrometry,N,
#------------------------
# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing_Values: NaN
age	Sr/Ca
1995.043	8.82
1995.050	8.82
1995.054	8.90
1995.060	9.28
1995.067	9.08
1995.077	8.96
1995.087	9.11
1995.139	8.72
1995.232	8.98
1995.308	8.94
1995.363	8.75
1995.423	9.14
1995.517	9.09
1995.575	8.65
1995.656	8.88
1995.693	8.81
1995.717	8.86
1995.740	8.92
1995.767	9.24
1995.789	8.98
1995.810	8.89
1995.841	9.32
1995.861	8.95
1995.883	9.00
1995.906	9.17
1995.927	9.14
1995.951	8.99
1995.974	9.38
1995.998	9.33
1996.018	9.25
1996.045	9.05
1996.068	8.91
1996.095	8.99
1996.112	9.14
1996.137	9.26
1996.160	9.02
1996.184	9.39
1996.209	9.22
1996.235	9.32
1996.265	8.83
1996.291	9.01
1996.313	9.14
1996.341	8.99
1996.365	9.01
1996.387	8.82
1996.454	9.17
1996.480	9.03
1996.502	8.98
1996.526	9.14
1996.556	8.85
1996.573	9.04
1996.595	8.98
1996.616	8.75
1996.638	9.02
1996.660	9.55
1996.682	9.03
1996.704	9.10
1996.728	9.09
1996.751	9.17
1996.769	8.73
1996.787	9.21
1996.806	9.04
1996.822	8.99
1996.838	9.10
1996.854	9.01
1996.868	8.99
1996.887	8.87
1996.899	8.98
1996.917	9.02
1996.932	9.33
1996.948	9.31
1996.964	9.07
1996.982	9.20
1997.000	9.42
1997.033	8.83
1997.062	9.26
1997.098	9.20
1997.127	8.95
1997.156	8.89
1997.178	8.96
1997.205	8.88
1997.237	9.25
1997.271	8.86
1997.309	9.37
1997.338	8.96
1997.366	8.84
1997.399	9.18
NaN	NaN
1988.896	9.25
1988.882	8.88
1988.859	9.15
1988.838	9.09
1988.819	9.20
1988.799	8.90
1988.776	8.80
1988.750	9.22
1988.729	8.91
1988.710	8.95
1988.690	9.13
1988.671	8.81
1988.643	9.07
1988.621	9.13
1988.601	9.22
1988.567	8.88
1988.538	9.12
1988.509	8.94
1988.495	9.21
1988.459	9.06
1988.427	9.02
1988.389	9.07
1988.357	9.16
1988.332	9.02
1988.307	9.11
1988.282	9.22
1988.257	9.08
1988.232	8.86
1988.207	8.99
1988.182	8.98
1988.157	9.07
1988.132	8.92
1988.107	9.09
1988.082	8.92
1988.057	9.44
1988.032	9.28
1988.007	9.03
1987.983	8.96
1987.958	8.98
1987.917	9.05
1987.876	8.88
1987.835	9.03
1987.794	9.29
1987.759	8.90
1987.724	9.01
1987.689	8.96
1987.654	9.01
1987.619	8.69
1987.584	8.81
1987.549	8.76
1987.514	9.08
1987.479	9.01
1987.444	9.02
1987.409	9.10
1987.375	8.96
1987.345	9.10
1987.324	9.05
1987.320	9.08
1987.309	9.23
1987.288	9.03
1987.249	8.87
1987.223	8.97
1987.198	9.08
1987.177	8.75
1987.149	9.09
1987.122	9.13
1987.085	9.03
1987.064	8.91
1987.040	9.23
1987.024	9.04
1987.009	9.04
1986.995	9.43
1986.980	9.16
1986.963	8.92
1986.945	8.97
1986.935	9.01
1986.921	8.96
1986.884	9.27
1986.866	8.83
1986.848	9.07
1986.837	8.77
1986.817	8.82
1986.801	9.24
1986.789	9.11
1986.778	8.86
1986.763	8.85
1986.743	8.74
1986.714	8.78
1986.678	9.18
1986.637	8.74
1986.610	9.06
1986.583	8.73
1986.556	8.96
1986.529	8.83
1986.502	9.05
1986.475	9.16
1986.448	8.93
1986.421	9.06
1986.394	9.15
1986.366	9.23
1986.339	8.87
1986.312	8.91
1986.285	8.86
1986.258	8.88
1986.231	9.24
1986.204	9.06
1986.187	9.05
1986.186	9.04
1986.185	8.92
1986.185	9.20
1986.165	9.28
1986.145	9.03
1986.124	9.27
1986.107	9.00
1986.094	9.47
1986.081	9.03
1986.068	8.85