EGU21-5941
https://doi.org/10.5194/egusphere-egu21-5941
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

A probabilistic approach to oxygen isotope modelling of speleothem data with age uncertainties

Josefine Axelsson1, Andreas Nilsson2, and Jesper Sjolte2
Josefine Axelsson et al.
  • 1Department of Physical Geography and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden (josefine.axelsson@natgeo.su.se)
  • 2Department of Geology, Lund University, Lund, Sweden

Due to age uncertainties and poor resolution in speleothems, age-depth modelling techniques are often implemented for cross-examinations. In this study, we use a variation of the analogue method to perform a pseudo-proxy reconstruction of the large-scale variability in Indian and East Asian monsoon precipitation using synthetic oxygen isotope records from speleothem sites and an isotope-enabled climate model.

We present a probabilistic approach to synchronize speleothems through oxygen isotope data and individual independent age constraints, achieved by co-estimating the regional δ18O variations through time. The δ18O variability is modelled using Gaussian processes, and an adaptation of BACON age-depth model is further used for the individual speleothem chronologies.

The method is tested using synthetic speleothem data generated from the ECHAM/MPI-OM climate model and corrupted through realistic noise from speleothems from the SISAL database.

By incorporating accurate and realistic depth-dependent age-uncertainties rather than shifting, stretching or compressing the time-series of oxygen isotope data, this modelling approach may lead to advancements of handling speleothem data for regional to global evaluations on variability between speleothems and timescales.

How to cite: Axelsson, J., Nilsson, A., and Sjolte, J.: A probabilistic approach to oxygen isotope modelling of speleothem data with age uncertainties, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5941, https://doi.org/10.5194/egusphere-egu21-5941, 2021.

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