Prey4PDV · New Paleo REanalYsis FOR improved understanding of Pacific Decadal Variability

The Pacific Decadal Variability (PDV) characterises the fluctuations in sea surface temperatures across the Pacific Ocean over decadal to multi-decadal timescales. As the primary driver of variability at these scales, PDV exerts a significant influence on the climate in surrounding regions. It contributes to significant regional climate events such as floods and bushfires while also playing a pivotal role at the global scale by amplifying and mitigating human-induced global warming. Despite a significant effort in recent years to understand the root mechanisms of PDV, our understanding remains hampered by the limited duration of instrumental observations that mainly cover the 20th century with large undercovered sub-regions. It ultimately inhibits the study of longer-term climate variations and especially the role of ocean dynamics. This knowledge gap significantly hampers our confidence in climate projections for the next few decades, particularly at the regional scale. Based on the knowledge of the applicant on the use of paleoclimate proxies combined with climate models to retrieve past climate changes and the expertise of the host institution on data assimilation and climate dynamics, Prey4PDV aims at providing the first paleoclimate reanalysis taking into account the exchanges between the atmosphere and ocean in the Pacific using a state-of-the-art Earth System Model over the past 500 years. Using the product together with sensitivity numerical simulations, we will investigate the critical drivers of the multi-decadal variability in the Pacific. During this fellowship, I will transfer my knowledge in using paleo records within an Earth System Model to the host institution, while learning state-of-the-art data assimilation methods, running numerical simulations, and tropical climate dynamics from the host institution. Therefore, this fellowship will place me at the forefront of an emerging scientific topic by applying state-of-the-art paleo data assimilation.