Reconstructing Holocene temperatures in time and space using paleoclimate data assimilation

Abstract. Paleoclimatic records provide valuable information about Holocene climate, revealing aspects of climate variability for a multitude sites around the world. However, such data also possess limitations. Proxy networks are spatially uneven, seasonally biased, uncertain in time, and present variety challenges when used concert to illustrate complex variations past climate. assimilation provides one approach reconstructing that can account diverse nature proxy while maintaining physics-based covariance structures simulated by models. Here, we use paleoclimate create complete reconstruction temperature over 12 000 years using from Temperature 12k database output transient model simulations. Following last glacial period, shows temperatures warming peak near 6400 ago followed slow cooling toward day, supporting mid-Holocene which is at least as warm preindustrial. Sensitivity tests show if proxies have an overlooked summer bias, some apparent warmth could actually represent trends rather than annual mean trends. Regardless, potential effects seasonal biases insufficient align reconstructed global with seen