A new bootstrap technique to quantify uncertainty in estimates of ground surface temperature and ground heat flux histories from geothermal data: global borehole inversions

Dataset overwiew This dataset includes global estimates of ground surface temperature for the period 1465-2000 C.E. The time series were created using the profiles available in the Xibalbá dataset (Cuesta-Valero et al., 2021a,b) and three different methods to estimate the global averages and uncertainties. The values were first retrieved and analyzed with the CIBOR v1 software (Cuesta-Valero et al., 2022a) as documented in Cuesta-Valero et al. (2022b). The datasets in this repository were created by applying three different methods to estimate global means and uncertainties:- The results of a typical Singular Value Decomposition (SVD) analysis based on Beltrami et al. (1992) are provided in the file `singular_value_decomposition.csv`.- The results of a perturbed parameter analysis of the thermal properties of the ground are provided in the file `perturbed_parameter_ensemble.csv`.- The results of a bootstraping estimate from a Monte-Carlo ensemble of inversions are provided in the file `bootstrapping.csv`. IMPORTANT: we recommend using the results of the file `bootstrapping.csv`. The other two files are provided for comparison purposes, but the results of the bootstraping technique are more robust (Cuesta-Valero et al., 2022a). Dataset contents The files contain the ground surface temperature histories from geothermal data from 1465 to 2000, the period with more than 200 subsurface temperature profiles. The first column corresponds to the year, the second column corresponds to the 2.5th percentile, the third column corresponds to the 50th percentile, the fourth column corresponds to the 97.5th percentile, and the fifth column corresponds to the number of subsurface temperature profiles available. All inversions were performed retaining the two largest eigenvalues in the SVD algorithm and considering a step change of 30 years in the retrieved surface signal. Inversions in the `singular_value_decomposition.csv` file consider a constant thermal diffusivity of 1.0e-6 m2 s-1, while the other two files consider a range of diffusivities between 0.5e-6 and 1.5e-6 m2 s-1. The `perturbed_parameter_ensemble.csv` file considers an ensemble of 100 members, while the `bootstrapping.csv` file considers a Monte-Carlo ensemble of 1000 members. Citation instructions Please, indicate the following reference when citing this dataset: Cuesta-Valero, F. J., Beltrami, H., Gruber, S., García-García, A., and González-Rouco, J. F.: A new bootstrap technique to quantify uncertainty in estimates of ground surface temperature and ground heat flux histories from geothermal data, Geosci. Model Dev., 15, 7913–7932, https://doi.org/10.5194/gmd-15-7913-2022, 2022a. Additional resources Access to the CIBOR v1 software used for inverting the profiles: Cuesta-Valero, F. J.: CIBOR: Codes for Inverting BOReholes (1.0.0), Zenodo [code], https://doi.org/10.5281/zenodo.7152900, 2022b. Access to the Xibalbá dataset: Cuesta-Valero, F. J., Beltrami, H., García-García, A., González-Rourco, J. F., and García-Bustamante, E.: Xibalbá: Underground Temperature Database, figshare [data set], https://doi.org/10.6084/m9.figshare.13516487.v4, 2021a. For further documentation about the inversion methods considered here: Beltrami, H., Jessop, A. M., and Mareschal, J.-C.: Ground temperature histories in eastern and central Canada from geothermal measurements: evidence of climatic change, Global Planet. Change, 6, 167–183, https://doi.org/10.1016/0921-8181(92)90033-7, 1992. Cuesta-Valero, F. J., García-García, A., Beltrami, H., González-Rouco, J. F., and García-Bustamante, E.: Long-term global ground heat flux and continental heat storage from geothermal data, Clim. Past, 17, 451-468, https://doi.org/10.5194/cp-17-451-2021, 2021b.