An emulator-based modelling framework for studying astronomical controls on ocean anoxia with an application to the Devonian

Abstract. We present a modelling framework to study the response of continental flux dynamics and ocean anoxia to astronomical forcing. The GEOCLIM model is coupled with a Gaussian Process-based climate emulator, designed to efficiently capture the global distribution of temperature and precipitation as simulated by the general circulation model HadCM3L. The emulator employs principal component analysis for dimensionality reduction. Compared to earlier approaches, our emulator features an additive kernel function that better captures the spatial complexity of ocean responses and accounts for ocean heat transport. This setup facilitates interactive coupling between CO2 levels through an iterative procedure involving GEOCLIM and the emulator, enabling systematic exploration of various orbital and pCO2 configurations. We demonstrate the model's capabilities with a Devonian case study, revealing an emergent relationship between high eccentricity periods and enhanced regolith development, though with limited impact on phosphorus fluxes to the ocean.