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  • Publication . Review . 2022
    Open Access
    Authors: 
    Janica Buehler;
    Publisher: Copernicus GmbH
  • Publication . Review . 2022
    Open Access
    Authors: 
    Janica Buehler;
    Publisher: Copernicus GmbH
  • Open Access
    Authors: 
    Janica C. Bühler; Josefine M. Axelsson; Franziska A. Lechleitner; Jens Fohlmeister; Allegra N. LeGrande; Madhavan Midhun; Jesper Sjolte; Martin Werner; Kei Yoshimura; Kira Rehfeld;
    Publisher: Copernicus GmbH
  • Open Access
    Authors: 
    Janica Bühler; Josefine Axelsson; Franziska A. Lechleitner; Jens Fohlmeister; Allegra N. LeGrande; Madhavan Midhun; Jesper Sjolte; Martin Werner; Kei Yoshimura; Kira Rehfeld;
    Publisher: Copernicus GmbH
    Project: SNSF | Exploring the potential o... (186693)

    Abstract. The incorporation of water isotopologues into the hydrology of general circulation models (GCMs) facilitates the comparison between modelled and measured proxy data in paleoclimate archives. However, the variability and drivers of measured and modelled water isotopologues, and indeed the diversity of their representation in different models are not well constrained. Improving our understanding of this variability in past and present climates will help to better constrain future climate change projections and decrease their range of uncertainty. Speleothems are a precisely datable paleoclimate archive and provide well preserved (semi-)continuous multivariate isotope time series in the lower and mid-latitudes, and are, therefore, well suited to assess climate and isotope variability on decadal and longer timescales. However, the relationship between speleothem oxygen and carbon isotopes to climate variables also depends on site-specific parameters, and their comparison to GCMs is not always straightforward. Here we compare speleothem oxygen and carbon isotopic signatures from the Speleothem Isotopes Synthesis and AnaLysis database version 2 (SISALv2) to the output of five different water-isotope-enabled GCMs (ECHAM5-wiso, GISS-E2-R, iCESM, iHadCM3, and isoGSM) over the last millennium (850–1850 common era, CE). We systematically evaluate differences and commonalities between the standardized model simulation outputs. The goal is to distinguish climatic drivers of variability for both modelled and measured isotopes. We find strong regional differences in the oxygen isotope signatures between models that can partly be attributed to differences in modelled temperatures. At low latitudes, precipitation amount is the dominant driver for water isotope variability, however, at cave locations the agreement between modelled temperature variability is higher than for precipitation variability. While modelled isotopic signatures at cave locations exhibited extreme events coinciding with changes in volcanic and solar forcing, such fingerprints are not apparent in the speleothem isotopes, and may be attributed to the lower temporal resolution of speleothem records compared to the events that are to be detected. Using spectral analysis, we can show that all models underestimate decadal and longer variability compared to speleothems, although to varying extent. We found that no model excels in all analyzed comparisons, although some perform better than the others in either mean or variability. Therefore, we advise a multi-model approach, whenever comparing proxy data to modelled data. Considering karst and cave internal processes through e.g. isotope-enabled karst models may alter the variability in speleothem isotopes and play an important role in determining the most appropriate model. By exploring new ways of analyzing the relationship between the oxygen and carbon isotopes, their variability, and co-variability across timescales, we provide methods that may serve as a baseline for future studies with different models using e.g. different isotopes, different climate archives, or time periods.

  • Open Access
    Authors: 
    Bühler, Janica C.; Axelsson, Josefine; Rehfeld, Kira; LeGrande, Allegra N.; Midhun, Madhavan; Sjolte, Jesper; Werner, Martin; Yoshimura, Kei;
    Publisher: Zenodo

    {"references": ["Brady, E., Stevenson, S., Bailey, D., Liu, Z., Noone, D., Nusbaumer, J., Otto-Bliesner, B. L., Tabor, C., Tomas, R., Wong, T., Zhang, J., and Zhu, J.: The Connected Isotopic Water Cycle in the Community Earth System Model Version 1, Journal of Advances in Modeling Earth Systems, 11, 2547\u20132566, 2019.", "B\u00fchler, J. C., Roesch, C., Kirschner, M., Sime, L., Holloway, M. D., and Rehfeld, K.: Comparison of the oxygen isotope signatures in speleothem records and iHadCM3 model simulations for the last millennium, Climate of the Past, 17, 985\u20131004, 2021.", "B\u00fchler, J. C., Axelsson, J. M., Lechleitner, F. A., Fohlmeister, J., LeGrande, A. N., Midhun, M., Sjolte, J., Werner, M., Yoshimura, K., and Rehfeld, K.: Investigating oxygen and carbon isotopic relationships in speleothem records over the last millennium using multiple isotope-enabled climate models, Clim. Past Discuss. [preprint], https://doi.org/10.5194/cp-2021-152, in review, 2021.", "Comas-Bru, L., Rehfeld, K., Roesch, C., Amirnezhad-Mozhdehi, S., Harrison, S. P., Atsawawaranunt, K., Ahmad, S. M., Ait Brahim, Y., Baker, A., Bosomworth, M., Breitenbach, S. F. M., Burstyn, Y., Columbu, A., Deininger, M., Dem\u00e9ny, A., Dixon, B., Fohlmeister, J., Hatvani, I. G., Hu, J., Kaushal, N., Kern, Z., Labuhn, I., Lechleitner, F. A., Lorrey, A., Martrat, B., Novello, V. F., Oster, J., P\u00e9rez-Mej\u00edas, C., Scholz, D., Scroxton, N., Sinha, N., Ward, B. M., Warken, S., Zhang, H., and the SISAL members: SISALv2: A comprehensive speleothem isotope database with multiple age-depth models, Earth Syst. Sci. Data, https://doi.org/10.5194/essd-2020-39, 2020.", "Colose, C. M., LeGrande, A. N., and Vuille, M.: The influence of volcanic eruptions on the climate of tropical South America during the last millennium in an isotope-enabled general circulation model, Climate of the Past, 12, 961\u2013979, 2016.", "Colose, C. M., LeGrande, A. N., and Vuille, M.: Hemispherically asymmetric volcanic forcing of tropical hydroclimate during the last millennium, Earth System Dynamics, 7, 681\u2013696, 2016.", "Lewis, S. C. and Legrande, A. N.: Stability of ENSO and its tropical Pacific teleconnections over the Last Millennium, Climate of the Past, 11, 1347\u20131360, 2015.", "Sjolte, J., Sturm, C., Adolphi, F., Vinther, B. M., Werner, M., Lohmann, G., and Muscheler, R.: Solar and volcanic forcing of North Atlantic climate inferred from a process-based reconstruction, Climate of the Past, 14, 1179\u20131194, 2018.", "Stevenson, S., Otto-Bliesner, B. L., Brady, E. C., Nusbaumer, J., Tabor, C., Tomas, R., Noone, D. C., and Liu, Z.: Volcanic Eruption Signatures in the Isotope-Enabled Last Millennium Ensemble, Paleoceanography and Paleoclimatology, 34, 1534\u20131552, 2019.", "Tindall, J. C., P. J. Valdes, and Louise C. Sime: Stable water isotopes in HadCM3: Isotopic signature of El Nino Southern Oscillation and the tropical amount effect. J. Geophys. Res.: Atm. 114.D4, 2009.", "Werner, M., Haese, B., Xu, X., Zhang, X., Butzin, M., and Lohmann, G.: Glacial-interglacial changes in H218O, HDO and deuterium excess-results from the fully coupled ECHAM5/MPI-OM Earth system model, Geoscientific Model Development, 9, 647\u2013670, 2016.", "Yoshimura, K., Kanamitsu, M., Noone, D., and Oki, T.: Historical isotope simulation using Reanalysis atmospheric data, Journal of Geophysical Research Atmospheres, 113, D19 108, 2008."]} Here we provide climate fields in monthly resolution for five isotope-enabled model: ECHAM5-wiso (Sjolte et al. 2018, Werner et al. 2016), GISS-E2-R (Lewis and Legrande 2015, Colose et al 2016), iCESM (Brady et al. 2019, Stevenson et al 2019), iHadCM3 (Bühler et al. 2021, Tindall et al. 2009), and isoGSM (Yoshimura et al. 2008) in supplement to Buehler et al. (2021, submitted to Clim. Past. Discuss.). The model simulations were performed with different sets of boundary conditions as described in Bühler et al. (2021, submitted to Clim. Past. Discuss.) in line with the PMIP3 protocoll (Schmidt et al. 2012). We provide output for surface temperature (in K), total precipitation amount (in mm month^-1), evaporation (in mm month^-1), latent heat (in W m^-2), and oxygen isotope ratios of precipitation (in permil). Additionally, we provide simulation output extracted at cave locations within the SISAL v.2. database (https://researchdata.reading.ac.uk/256/, Comas-Bru et al. (2020)). We include output for sites that pass the resolution and dating screening, meaning that have at least 2 radiometric dates (or are lamina-counted) and provide 36 oxygen isotope ratio measurements within the last millennium. In order to assure traceability, any presentation, report, or publication that uses the multi-model ensemble should cite Bühler et at. 2021 (submitted to Clim. Past. Discuss.) and the original publications of the respective simulations used.

Include:
5 Research products, page 1 of 1
  • Publication . Review . 2022
    Open Access
    Authors: 
    Janica Buehler;
    Publisher: Copernicus GmbH
  • Publication . Review . 2022
    Open Access
    Authors: 
    Janica Buehler;
    Publisher: Copernicus GmbH
  • Open Access
    Authors: 
    Janica C. Bühler; Josefine M. Axelsson; Franziska A. Lechleitner; Jens Fohlmeister; Allegra N. LeGrande; Madhavan Midhun; Jesper Sjolte; Martin Werner; Kei Yoshimura; Kira Rehfeld;
    Publisher: Copernicus GmbH
  • Open Access
    Authors: 
    Janica Bühler; Josefine Axelsson; Franziska A. Lechleitner; Jens Fohlmeister; Allegra N. LeGrande; Madhavan Midhun; Jesper Sjolte; Martin Werner; Kei Yoshimura; Kira Rehfeld;
    Publisher: Copernicus GmbH
    Project: SNSF | Exploring the potential o... (186693)

    Abstract. The incorporation of water isotopologues into the hydrology of general circulation models (GCMs) facilitates the comparison between modelled and measured proxy data in paleoclimate archives. However, the variability and drivers of measured and modelled water isotopologues, and indeed the diversity of their representation in different models are not well constrained. Improving our understanding of this variability in past and present climates will help to better constrain future climate change projections and decrease their range of uncertainty. Speleothems are a precisely datable paleoclimate archive and provide well preserved (semi-)continuous multivariate isotope time series in the lower and mid-latitudes, and are, therefore, well suited to assess climate and isotope variability on decadal and longer timescales. However, the relationship between speleothem oxygen and carbon isotopes to climate variables also depends on site-specific parameters, and their comparison to GCMs is not always straightforward. Here we compare speleothem oxygen and carbon isotopic signatures from the Speleothem Isotopes Synthesis and AnaLysis database version 2 (SISALv2) to the output of five different water-isotope-enabled GCMs (ECHAM5-wiso, GISS-E2-R, iCESM, iHadCM3, and isoGSM) over the last millennium (850–1850 common era, CE). We systematically evaluate differences and commonalities between the standardized model simulation outputs. The goal is to distinguish climatic drivers of variability for both modelled and measured isotopes. We find strong regional differences in the oxygen isotope signatures between models that can partly be attributed to differences in modelled temperatures. At low latitudes, precipitation amount is the dominant driver for water isotope variability, however, at cave locations the agreement between modelled temperature variability is higher than for precipitation variability. While modelled isotopic signatures at cave locations exhibited extreme events coinciding with changes in volcanic and solar forcing, such fingerprints are not apparent in the speleothem isotopes, and may be attributed to the lower temporal resolution of speleothem records compared to the events that are to be detected. Using spectral analysis, we can show that all models underestimate decadal and longer variability compared to speleothems, although to varying extent. We found that no model excels in all analyzed comparisons, although some perform better than the others in either mean or variability. Therefore, we advise a multi-model approach, whenever comparing proxy data to modelled data. Considering karst and cave internal processes through e.g. isotope-enabled karst models may alter the variability in speleothem isotopes and play an important role in determining the most appropriate model. By exploring new ways of analyzing the relationship between the oxygen and carbon isotopes, their variability, and co-variability across timescales, we provide methods that may serve as a baseline for future studies with different models using e.g. different isotopes, different climate archives, or time periods.

  • Open Access
    Authors: 
    Bühler, Janica C.; Axelsson, Josefine; Rehfeld, Kira; LeGrande, Allegra N.; Midhun, Madhavan; Sjolte, Jesper; Werner, Martin; Yoshimura, Kei;
    Publisher: Zenodo

    {"references": ["Brady, E., Stevenson, S., Bailey, D., Liu, Z., Noone, D., Nusbaumer, J., Otto-Bliesner, B. L., Tabor, C., Tomas, R., Wong, T., Zhang, J., and Zhu, J.: The Connected Isotopic Water Cycle in the Community Earth System Model Version 1, Journal of Advances in Modeling Earth Systems, 11, 2547\u20132566, 2019.", "B\u00fchler, J. C., Roesch, C., Kirschner, M., Sime, L., Holloway, M. D., and Rehfeld, K.: Comparison of the oxygen isotope signatures in speleothem records and iHadCM3 model simulations for the last millennium, Climate of the Past, 17, 985\u20131004, 2021.", "B\u00fchler, J. C., Axelsson, J. M., Lechleitner, F. A., Fohlmeister, J., LeGrande, A. N., Midhun, M., Sjolte, J., Werner, M., Yoshimura, K., and Rehfeld, K.: Investigating oxygen and carbon isotopic relationships in speleothem records over the last millennium using multiple isotope-enabled climate models, Clim. Past Discuss. [preprint], https://doi.org/10.5194/cp-2021-152, in review, 2021.", "Comas-Bru, L., Rehfeld, K., Roesch, C., Amirnezhad-Mozhdehi, S., Harrison, S. P., Atsawawaranunt, K., Ahmad, S. M., Ait Brahim, Y., Baker, A., Bosomworth, M., Breitenbach, S. F. M., Burstyn, Y., Columbu, A., Deininger, M., Dem\u00e9ny, A., Dixon, B., Fohlmeister, J., Hatvani, I. G., Hu, J., Kaushal, N., Kern, Z., Labuhn, I., Lechleitner, F. A., Lorrey, A., Martrat, B., Novello, V. F., Oster, J., P\u00e9rez-Mej\u00edas, C., Scholz, D., Scroxton, N., Sinha, N., Ward, B. M., Warken, S., Zhang, H., and the SISAL members: SISALv2: A comprehensive speleothem isotope database with multiple age-depth models, Earth Syst. Sci. Data, https://doi.org/10.5194/essd-2020-39, 2020.", "Colose, C. M., LeGrande, A. N., and Vuille, M.: The influence of volcanic eruptions on the climate of tropical South America during the last millennium in an isotope-enabled general circulation model, Climate of the Past, 12, 961\u2013979, 2016.", "Colose, C. M., LeGrande, A. N., and Vuille, M.: Hemispherically asymmetric volcanic forcing of tropical hydroclimate during the last millennium, Earth System Dynamics, 7, 681\u2013696, 2016.", "Lewis, S. C. and Legrande, A. N.: Stability of ENSO and its tropical Pacific teleconnections over the Last Millennium, Climate of the Past, 11, 1347\u20131360, 2015.", "Sjolte, J., Sturm, C., Adolphi, F., Vinther, B. M., Werner, M., Lohmann, G., and Muscheler, R.: Solar and volcanic forcing of North Atlantic climate inferred from a process-based reconstruction, Climate of the Past, 14, 1179\u20131194, 2018.", "Stevenson, S., Otto-Bliesner, B. L., Brady, E. C., Nusbaumer, J., Tabor, C., Tomas, R., Noone, D. C., and Liu, Z.: Volcanic Eruption Signatures in the Isotope-Enabled Last Millennium Ensemble, Paleoceanography and Paleoclimatology, 34, 1534\u20131552, 2019.", "Tindall, J. C., P. J. Valdes, and Louise C. Sime: Stable water isotopes in HadCM3: Isotopic signature of El Nino Southern Oscillation and the tropical amount effect. J. Geophys. Res.: Atm. 114.D4, 2009.", "Werner, M., Haese, B., Xu, X., Zhang, X., Butzin, M., and Lohmann, G.: Glacial-interglacial changes in H218O, HDO and deuterium excess-results from the fully coupled ECHAM5/MPI-OM Earth system model, Geoscientific Model Development, 9, 647\u2013670, 2016.", "Yoshimura, K., Kanamitsu, M., Noone, D., and Oki, T.: Historical isotope simulation using Reanalysis atmospheric data, Journal of Geophysical Research Atmospheres, 113, D19 108, 2008."]} Here we provide climate fields in monthly resolution for five isotope-enabled model: ECHAM5-wiso (Sjolte et al. 2018, Werner et al. 2016), GISS-E2-R (Lewis and Legrande 2015, Colose et al 2016), iCESM (Brady et al. 2019, Stevenson et al 2019), iHadCM3 (Bühler et al. 2021, Tindall et al. 2009), and isoGSM (Yoshimura et al. 2008) in supplement to Buehler et al. (2021, submitted to Clim. Past. Discuss.). The model simulations were performed with different sets of boundary conditions as described in Bühler et al. (2021, submitted to Clim. Past. Discuss.) in line with the PMIP3 protocoll (Schmidt et al. 2012). We provide output for surface temperature (in K), total precipitation amount (in mm month^-1), evaporation (in mm month^-1), latent heat (in W m^-2), and oxygen isotope ratios of precipitation (in permil). Additionally, we provide simulation output extracted at cave locations within the SISAL v.2. database (https://researchdata.reading.ac.uk/256/, Comas-Bru et al. (2020)). We include output for sites that pass the resolution and dating screening, meaning that have at least 2 radiometric dates (or are lamina-counted) and provide 36 oxygen isotope ratio measurements within the last millennium. In order to assure traceability, any presentation, report, or publication that uses the multi-model ensemble should cite Bühler et at. 2021 (submitted to Clim. Past. Discuss.) and the original publications of the respective simulations used.

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