d13CairCO2_LOESS_Interpolation

This is a smoothed curve of d13C in atmospheric CO2 from 16100 BCE to 2010 CE, based on data from Antarctic ice-cores (Eyer & Leuenberger, pers. comm.; Francey et al., 1999; Indermühle et al., 1999;Leuenberger et al., 1992) and flask data from two Antarctic stations (Halley Bay and Palmer Station) of the NOAA ESRL Carbon Cycle Cooperative Global Air Sampling Network. If you use the interpolation curve, please ALWAYS refer to: 1) the NOAA ESRL Carbon Cycle Cooperative Global Air Sampling Network: https://gml.noaa.gov/aftp/data/trace_gases/co2c13/flask/README_surface_flask_co2c13.html 2) the original publication of the interpolation curve: Ferrio JP, Araus JL, Buxó R, Voltas J, Bort J (2005) Water management practices and climate in ancient agriculture: inference from the stable isotope composition of archaeobotanical remains. Vegetation History and Archaeobotany 14:510-517 Please cite also the original references of ice-core data: Francey RJ, Allison CE, Etheridge DM, Trudinger CM, Enting IG, Leuenberger M, Langenfelds RL, Michel E, Steele LP (1999) A 1000-year high precision record of delta C-13 in atmospheric CO2. Tellus B 51:170-193 Indermühle A, Stocker TF, Joos F, Fischer H, Smith HJ, Wahlen M, Deck B, Mastroianni D, Tschumi J, Blunier T, Meyer R, Stauffer B (1999) Holocene carbon-cycle dynamics based on CO2 trapped in ice at Taylor Dome, Antarctica. Nature 398:121-126 Leuenberger M, Siegenthaler U, Langway CC (1992) Carbon isotope composition of atmospheric CO2 during the last ice age from an Antartic ice core. Nature 357:488-490 IMPORTANT NOTE: this dataset should be only used to apply the interpolation curve, e.g. as reference for d13C in archaeobotanical, wood charcoal or tree-rings Original values from ice-cores and NOAA ESRL should be retrieved (and cited) from their original sources BEAR IN MIND THAT THIS IS AN APPROXIMATION: 1) Ice core data, particularly regarding trapped CO2, has considerably dating errors 2) The data is based on Antarctic ice cores only. Considerable spatial variability in CO2 is expected METHODS: Due to the much higher time resolution available for the last 2 centuries, the smoothing was performed dividing the data in two overlapping sections (-16100 to 1800) and (1760-2003). The smoothing was done by fitting locally weighted least squares (LOESS) regression curves (Cleveland 1979) with a span of 0.1 and 0.4 for the first and second section, respectively. References Cleveland WS (1979) Robust locally weighted regression and smoothing scatterplots. Journal of the American Statistical Association 74:829-836 Contact: https://www.juanpedroferrio.com/本数据集为公元前16100年至公元2010年大气二氧化碳中d¹³C的平滑曲线，数据源自南极冰芯（Eyer与Leuenberger，私人通信；Francey等，1999；Indermühle等，1999；Leuenberger等，1992），以及NOAA ESRL碳循环协作全球空气采样网络旗下两个南极站点（哈雷湾站与帕尔默站）的气瓶采样（flask）数据。 若使用该插值曲线，请务必引用以下来源： 1) NOAA ESRL碳循环协作全球空气采样网络：https://gml.noaa.gov/aftp/data/trace_gases/co2c13/flask/README_surface_flask_co2c13.html 2) 该插值曲线的原始文献：Ferrio JP, Araus JL, Buxó R, Voltas J, Bort J (2005) 古代农业的水管理实践与气候：基于考古植物遗存稳定同位素组成的推断. 《植被历史与考古植物学（Vegetation History and Archaeobotany）》14卷：510-517 同时请一并引用冰芯数据的原始文献： Francey RJ, Allison CE, Etheridge DM, Trudinger CM, Enting IG, Leuenberger M, Langenfelds RL, Michel E, Steele LP (1999) 大气CO₂中d¹³C的千年高精度记录. 《Tellus B》51卷：170-193 Indermühle A, Stocker TF, Joos F, Fischer H, Smith HJ, Wahlen M, Deck B, Mastroianni D, Tschumi J, Blunier T, Meyer R, Stauffer B (1999) 基于南极泰勒穹顶冰芯封存CO₂的全新世碳循环动力学. 《Nature》398卷：121-126 Leuenberger M, Siegenthaler U, Langway CC (1992) 末次冰期大气CO₂的碳同位素组成：来自南极冰芯的证据. 《Nature》357卷：488-490 重要提示：本数据集仅可用于插值曲线的应用场景，例如作为考古植物遗存、木炭或树木年轮中d¹³C的参考标准。冰芯与NOAA ESRL的原始数据请从其原始来源获取并引用。 请注意以下近似性说明： 1) 冰芯数据，尤其是封存的CO₂，存在显著的定年误差 2) 本数据仅基于南极冰芯，预计CO₂存在显著的空间变异性 方法：由于近两个世纪的时间分辨率更高，本次平滑处理将数据分为两个重叠区间（公元前16100年至1800年，以及1760年至2003年）。平滑处理通过拟合局部加权最小二乘（LOESS）回归曲线（Cleveland，1979）完成，两个区间的平滑跨度分别为0.1和0.4。 参考文献：Cleveland WS (1979) 稳健局部加权回归与平滑散点图. 《美国统计协会期刊》74卷：829-836 联系方式：https://www.juanpedroferrio.com/