d13CairCO2_LOESS_Interpolation
Description
This is a smoothed curve of d13C of atmospheric CO2 from 16100 BCE to 2010 CE derived a range of data from Antarctic ice-core records (Eyer & Leuenberger, pers. comm.; Francey et al., 1999; Indermühle et al., 1999;Leuenberger et al., 1992) together with modern data from two Antarctic stations (Halley Bay and Palmer Station) of the NOAA ESRL Carbon Cycle Cooperative Global Air Sampling Network. contact: https://www.juanpedroferrio.com/ 03-04-2023 CO2 flask data updated for the period 1995-2014, Included linear extrapolation (2003-2014) until 2025 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 published references of ice-core data: Cleveland WS (1979) Robust locally weighted regression and smoothing scatterplots. Journal of the American Statistical Association 74:829-836 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 COMMENTS: 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. NOTE: the source data included here should be only used to apply the interpolation curve, 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