Reconstruction of Holocene Northern Hemisphere precipitation fields using paleoclimate data assimilation

Clarifying the spatiotemporal patterns of Holocene (~11.7 - 0 ka BP) precipitation variability over the Northern Hemisphere (NH) is essential for contextualizing modern hydroclimate variability. However, the scarcity of spatiotemporally-completed, temporally well-resolved and highly-reliable reconstructions has limited a full-field understanding of Holocene hydroclimate. Here, we present a reconstruction of NH annual precipitation spanning 12-0 ka BP at 3.75° spatial and 100-year temporal resolution. This dataset was generated using paleoclimate data assimilation (PDA) approach, integrating 2,421 Holocene precipitation records with two transient simulations via an Ensemble Optimal Interpolation algorithm. Validation suggested the PDA-based reconstructions have significantly improved reliability compared to model-only simulations, particularly at mid-high latitudes. As a core product of the Holocene Climate Reanalysis supported by Chinese Academy of Sciences (CAS-HCR), this dataset represents a substantial progress in applying the PDA approach to reconstruct Holocene precipitation fields at hemispherical scale, and provides a key resource for analyzing the spatiotemporal dynamics of Holocene hydroclimate, contextualizing modern precipitation changes and evaluating the performance of climate models in simulating long-term precipitation variability.