Preprints
https://doi.org/10.5194/essd-2025-517
https://doi.org/10.5194/essd-2025-517
01 Sep 2025
 | 01 Sep 2025
Status: this preprint is currently under review for the journal ESSD.

Reconstruction of δ13CDIC in the Atlantic Ocean: A Probabilistic Machine Learning Approach for Filling Historical Data Gaps

Hui Gao, Zelun Wu, Zhentao Sun, Diana Cai, Meibing Jin, and Wei-Jun Cai

Abstract. Stable carbon isotope composition of marine dissolved inorganic carbon (DIC), δ13CDIC, is a valuable tracer for oceanic carbon cycling. However, its observational coverage remains much sparser than that of DIC and other physical or biogeochemical variables, limiting its full potential. Here, we reconstruct δ13CDIC in the Atlantic Ocean using a probabilistic machine learning framework, Gaussian Process Regression (GPR). We compiled data from 51 historical cruises, including a high-resolution 2023 A16N section, and applied secondary quality control via crossover analysis, retaining 37 cruises for model training, validation, and testing. The trained GPR model achieved an average bias of −0.007 ± 0.082 ‰ and an overall uncertainty of 0.11 ‰, arising from measurement (0.07 ‰), mapping (0.08 ‰), and negligible input-variable (3.77 × 10−14 ‰) errors. Using the GLODAPv2.2023 Atlantic dataset as predictors, the reconstruction expanded the number of acceptable δ13CDIC samples by a factor of 7.65, from 8,941 to 68,435 across the Atlantic basins. The resulting dataset markedly improves the spatial resolution in longitude, latitude, and depth, and provides enhanced temporal continuity over the past four decades. Compared to the sparse original measurements, the reconstruction reduces spatial discontinuities and reveals finer vertical structures consistent with other high-resolution biogeochemical observations. This reconstructed δ13CDIC dataset provides new opportunities to resolve regional carbon cycle dynamics, validate Earth system models, refine estimates of oceanic carbon uptake, and extend climate reanalysis records. The data are publicly accessible at the data repository Zenodo under the following DOI: https://doi.org/10.5281/zenodo.16907402 (Gao et al., 2025).

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Share
Hui Gao, Zelun Wu, Zhentao Sun, Diana Cai, Meibing Jin, and Wei-Jun Cai

Status: open (until 08 Oct 2025)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Hui Gao, Zelun Wu, Zhentao Sun, Diana Cai, Meibing Jin, and Wei-Jun Cai

Data sets

Reconstruction of δ13CDIC in the Atlantic Ocean: A Probabilistic Machine Learning Approach for Filling Historical Data Gaps Hui Gao, Zelun Wu, Zhentao Sun, Diana Cai, Meibing Jin, Wei-Jun Cai https://doi.org/10.5281/zenodo.16907402

Hui Gao, Zelun Wu, Zhentao Sun, Diana Cai, Meibing Jin, and Wei-Jun Cai

Viewed

Total article views: 98 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
90 6 2 98 1 1
  • HTML: 90
  • PDF: 6
  • XML: 2
  • Total: 98
  • BibTeX: 1
  • EndNote: 1
Views and downloads (calculated since 01 Sep 2025)
Cumulative views and downloads (calculated since 01 Sep 2025)

Viewed (geographical distribution)

Total article views: 98 (including HTML, PDF, and XML) Thereof 98 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 04 Sep 2025
Download
Short summary
Observations of stable carbon isotopes in dissolved inorganic carbon are sparse, limiting their potential in carbon cycle studies. We compiled 51 cruises and used a machine learning method trained on 37 cruises that passed secondary quality control to reconstruct isotope values in the Atlantic. The reconstruction expands usable samples from 8,941 to 68,435, reducing noise, filling gaps, preserving decadal trend, and strengthening studies of carbon variability and model validation.
Share
Altmetrics