Ocean Circulation AcRoss Interglacials and deglacIatioNs through a reAnalysis framework

Objective

OCARINA aims to reconstruct the dynamics of the Atlantic Meridional Overturning Circulation (AMOC) during past Interglacial periods (Marine Isotopic Stages 7 and 9), which serve as natural analogues to current and future warm climates. These periods were characterized by high greenhouse gas concentrations and insolation levels, yet the structure and mechanism behind AMOC variability during these periods remain poorly constrained. Understanding AMOC sensitivity under such conditions is essential for anticipating its potential response to anthropogenic forcing. To adress this, the project will implement a pioneering approach: the first application of online data assimilation (DA) to paleoclimate reconstructions for these periods, using the Earth system model of intermediate complexity LOVECLIM. High-resolution Sea Surface Temperature (SST) and deep-ocean (benthic carbon isotopes) data will be assimilated using sequential particle filter, dynamically updating the model state to produce consistent observation-constrained reconstructions of ocean circulation. The project is structured into three objectives: (1) benchmark the model performance with and without DA; (2) produce the first online reanalysis of AMOC variability across a glacial-interglacial transitions; and (3) identify the physical drivers behind AMOC shifts. I bring complementary expertise in paleo-data analysis and proxy compilations, while the host institution provides leading expertise in climate modelling and DA techniques. OCARINA will enhance my interdisciplinary skills and visibility within the scientific community, while delivering open-access datasets, methodological protocols, and a novel DA framework for the broader climate science community. The project will advance the understanding of AMOC behaviour under natural warm climates and support future climate risk assessments.