Articles | Volume 19, issue 10
https://doi.org/10.5194/tc-19-4913-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-19-4913-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The impact of measurement precision on the resolvable resolution of ice core water isotope reconstructions
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Thomas Münch
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Vasileios Gkinis
Niels Bohr Institute, Physics of Ice, Climate, and Earth, University of Copenhagen, Copenhagen, Denmark
Thomas Laepple
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
MARUM – Centre for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany
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Cited articles
Bazin, L., Landais, A., Lemieux-Dudon, B., Toyé Mahamadou Kele, H., Veres, D., Parrenin, F., Martinerie, P., Ritz, C., Capron, E., Lipenkov, V., Loutre, M.-F., Raynaud, D., Vinther, B., Svensson, A., Rasmussen, S. O., Severi, M., Blunier, T., Leuenberger, M., Fischer, H., Masson-Delmotte, V., Chappellaz, J., and Wolff, E.: An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120–800 ka, Clim. Past, 9, 1715–1731, https://doi.org/10.5194/cp-9-1715-2013, 2013. a
Brent, R. P.: Algorithms for minimization without derivatives, Prentice-Hall, ISBN 9780130223357, 1973. a
Casado, M., Münch, T., and Laepple, T.: Climatic information archived in ice cores: impact of intermittency and diffusion on the recorded isotopic signal in Antarctica, Clim. Past, 16, 1581–1598, https://doi.org/10.5194/cp-16-1581-2020, 2020. a
Cellier, N. and Ruyer-Quil, C.: scikit-finite-diff, a new tool for PDE solving, J. Open Source Softw., 4, 1356, https://doi.org/10.21105/joss.01356, 2019. a
Chung, A., Parrenin, F., Steinhage, D., Mulvaney, R., Martín, C., Cavitte, M. G. P., Lilien, D. A., Helm, V., Taylor, D., Gogineni, P., Ritz, C., Frezzotti, M., O'Neill, C., Miller, H., Dahl-Jensen, D., and Eisen, O.: Stagnant ice and age modelling in the Dome C region, Antarctica, The Cryosphere, 17, 3461–3483, https://doi.org/10.5194/tc-17-3461-2023, 2023. a, b
Cochran, W. T., Cooley, J. W., Favin, D. L., Helms, H. D., Kaenel, R. A., Lang, W. W., Maling, G. C., Nelson, D. E., Rader, C. M., and Welch, P. D.: What is the fast Fourier transform?, Proc. IEEE, 55, 1664–1674, 1967. a
Dansgaard, W.: Stable isotopes in precipitation, Tellus, 16, 436–468, 1964. a
Fischer, H., Severinghaus, J., Brook, E., Wolff, E., Albert, M., Alemany, O., Arthern, R., Bentley, C., Blankenship, D., Chappellaz, J., Creyts, T., Dahl-Jensen, D., Dinn, M., Frezzotti, M., Fujita, S., Gallee, H., Hindmarsh, R., Hudspeth, D., Jugie, G., Kawamura, K., Lipenkov, V., Miller, H., Mulvaney, R., Parrenin, F., Pattyn, F., Ritz, C., Schwander, J., Steinhage, D., van Ommen, T., and Wilhelms, F.: Where to find 1.5 million yr old ice for the IPICS “Oldest-Ice” ice core, Clim. Past, 9, 2489–2505, https://doi.org/10.5194/cp-9-2489-2013, 2013. a
Fisher, D. A., Reeh, N., and Clausen, H.: Stratigraphic noise in time series derived from ice cores, Ann. Glaciol., 7, 76–83, 1985. a
Gkinis, V., Popp, T. J., Blunier, T., Bigler, M., Schüpbach, S., Kettner, E., and Johnsen, S. J.: Water isotopic ratios from a continuously melted ice core sample, Atmos. Meas. Tech., 4, 2531–2542, https://doi.org/10.5194/amt-4-2531-2011, 2011. a
Gkinis, V., Dahl-Jensen, D., Steffensen, J. P., Vinther, B. M., Landais, A., Jouzel, J., Masson-Delmotte, V., Cattani, O., Minster, B., Grisart, A., Hörhold, M., Stenni, B., and Selmo, E.: Oxygen-18 isotope ratios from the EPICA Dome C ice core at 11 cm resolution, PANGAEA [data set], https://doi.org/10.1594/PANGAEA.939445, 2021a. a
Gkinis, V., Holme, C., Kahle, E. C., Stevens, M. C., Steig, E. J., and Vinther, B. M.: Numerical experiments on firn isotope diffusion with the Community Firn Model, J. Glaciol., 67, 450–472, https://doi.org/10.1017/jog.2021.1, 2021b. a
Grisart, A., Casado, M., Gkinis, V., Vinther, B., Naveau, P., Vrac, M., Laepple, T., Minster, B., Prié, F., Stenni, B., Fourré, E., Steen-Larsen, H. C., Jouzel, J., Werner, M., Pol, K., Masson-Delmotte, V., Hoerhold, M., Popp, T., and Landais, A.: Sub-millennial climate variability from high-resolution water isotopes in the EPICA Dome C ice core, Clim. Past, 18, 2289–2301, https://doi.org/10.5194/cp-18-2289-2022, 2022. a
Huybers, P. and Curry, W.: Links between annual, Milankovitch and continuum temperature variability, Nature, 441, 329–332, 2006. a
Johnsen, S. J., Clausen, H. B., Dansgaard, W., Gundestrup, N. S., Hammer, C. U., Andersen, U., Andersen, K. K., Hvidberg, C. S., Dahl-Jensen, D., Steffensen, J. P., Shoji, H., Sveinbjörnsdóttir, A. E., White, J., Jouzel, J., and Fisher, D.: The δ18O record along the Greenland Ice Core Project deep ice core and the problem of possible Eemian climatic instability, J. Geophys. Res.-Oceans, 102, 26397–26410, 1997. a
Jones, E., Oliphant, T., and Peterson, P.: SciPy: Open source scientific tools for Python, http://www.scipy.org/ (last access: October 2024), 2001. a
Jones, T., Cuffey, K., White, J., Steig, E., Buizert, C., Markle, B., McConnell, J., and Sigl, M.: Water isotope diffusion in the WAIS Divide ice core during the Holocene and last glacial, J. Geophys. Res.-Earth Surf., 122, 290–309, 2017. a
Kahle, E. C., Holme, C., Jones, T. R., Gkinis, V., and Steig, E. J.: A generalized approach to estimating diffusion length of stable water isotopes from ice-core data, J. Geophys. Res.-Earth Surf., 123, 2377–2391, 2018. a
Laepple, T. and Huybers, P.: Ocean surface temperature variability: Large model–data differences at decadal and longer periods, P. Natl. Acad. Sci. USA, 111, 16682–16687, 2014. a
Lilien, D. A., Steinhage, D., Taylor, D., Parrenin, F., Ritz, C., Mulvaney, R., Martín, C., Yan, J.-B., O'Neill, C., Frezzotti, M., Miller, H., Gogineni, P., Dahl-Jensen, D., and Eisen, O.: Brief communication: New radar constraints support presence of ice older than 1.5 Myr at Little Dome C, The Cryosphere, 15, 1881–1888, https://doi.org/10.5194/tc-15-1881-2021, 2021. a, b, c
Liu, H., Meyers, S. R., and Marcott, S. A.: Unmixing deep-sea paleoclimate records: A study on bioturbation effects through convolution and deconvolution, Earth Planet. Sc. Lett., 564, 116883, https://doi.org/10.1016/j.epsl.2021.116883, 2021. a
Lliboutry, L.: A critical review of analytical approximate solutions for steady state velocities and temperatures in cold ice-sheets, Zeitschrift für Gletscherkunde und Glazialgeologie, 15, 135–148, 1979. a
Münch, T. and Laepple, T.: What climate signal is contained in decadal- to centennial-scale isotope variations from Antarctic ice cores?, Clim. Past, 14, 2053–2070, https://doi.org/10.5194/cp-14-2053-2018, 2018. a
NEEM community members: Eemian interglacial reconstructed from a Greenland folded ice core, Nature, 493, 489–494, 2013. a
NGRIP members: High-resolution record of Northern Hemisphere climate extending into the last interglacial period, Nature, 431, 147–151, 2004. a
Nye, J.: Diffusion of isotopes in the annual layers of ice sheets, J. Glaciol., 44, 467–468, 1998. a
Parrenin, F., Cavitte, M. G. P., Blankenship, D. D., Chappellaz, J., Fischer, H., Gagliardini, O., Masson-Delmotte, V., Passalacqua, O., Ritz, C., Roberts, J., Siegert, M. J., and Young, D. A.: Is there 1.5-million-year-old ice near Dome C, Antarctica?, The Cryosphere, 11, 2427–2437, https://doi.org/10.5194/tc-11-2427-2017, 2017. a
Pelletier, J. D.: The power spectral density of atmospheric temperature from time scales of 10−2 to 106 yr, Earth Planet. Sc. Lett., 158, 157–164, 1998. a
Percival, D. B. and Walden, A. T.: Spectral analysis for physical applications, cambridge university press, ISBN 9780521435413, 1993. a
Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N. I., Barnola, J.-M., Basile, I., Bender, M., Chappellaz, J., Davis, M., Delaygue, G., Delmotte, M., Kotlyakov, V. M., Legrand, M., Lipenkov, V. Y., Loruis, C., Pépin, L., Ritz, C., Saltzman, E., and Stievenard, M.: Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica, Nature, 399, 429–436, 1999. a
Shaw, F.: water_isotope_noise_vs_deconvolution, Zenodo [code], https://doi.org/10.5281/zenodo.16852149, 2025. a
Shaw, F., Dolman, A. M., Kunz, T., Gkinis, V., and Laepple, T.: Novel approach to estimate the water isotope diffusion length in deep ice cores with an application to Marine Isotope Stage 19 in the Dome C ice core, The Cryosphere, 18, 3685–3698, https://doi.org/10.5194/tc-18-3685-2024, 2024. a, b, c
Steen-Larsen, H. C. and Zannoni, D.: A versatile water vapor generation module for vapor isotope calibration and liquid isotope measurements, Atmos. Meas. Tech., 17, 4391–4409, https://doi.org/10.5194/amt-17-4391-2024, 2024. a
Thomson, D. J.: Spectrum estimation and harmonic analysis, Proc. IEEE, 70, 1055–1096, 1982. a
Van Liefferinge, B., Pattyn, F., Cavitte, M. G. P., Karlsson, N. B., Young, D. A., Sutter, J., and Eisen, O.: Promising Oldest Ice sites in East Antarctica based on thermodynamical modelling, The Cryosphere, 12, 2773–2787, https://doi.org/10.5194/tc-12-2773-2018, 2018. a
Whillans, I. and Grootes, P.: Isotopic diffusion in cold snow and firn, J. Geophys. Res.-Atmos., 90, 3910–3918, 1985. a
Short summary
Diffusion in combination with measurement noise erase high-frequency water isotope variability in ice cores, linking measurement precision to recoverable resolution. We derive expressions for this relationship, finding a resolution improvement of 1.5 times for a 10-fold measurement noise reduction. Based on the current age-depth model, our method predicts 10 000-year cycles will be recoverable in the 1.5 Myr old ice from the Oldest Ice Core δ18O record if a noise level of 0.01 ‰ is achieved.
Diffusion in combination with measurement noise erase high-frequency water isotope variability...