We examine the skill of a novel data assimilation approach to paleoclimate reconstruction that uses linear climate model forecasts. Many reconstruction studies forego the use of forecasts from climate models due to their high computational expense and relatively low skill. We show that the use of simpler linear models can improve reconstruction skill for both global mean temperature and spatial fields. Improvements displayed seem to be related to dynamical constraints from the forecasts.

A 120 m ice core from Mill Island, East Antarctica, was studied its chemical components. The Mill Island ice core contains 97 years of climate record (1913–2009) and has a mean snow accumulation of 1.35 m yr⁻¹ (ice equivalent). Trace ion concentrations were generally higher than other Antarctic ice core sites. Nearby sea ice concentration was found to influence the annual mean sea salt record. The Mill Island ice core records are unexpectedly complex, with strong modulation of the trace chemistry.

Initial and boundary condition data from the 20th Century Reanalysis Project in ensemble mode are used to address the feasibility of performing cloud-resolving simulations with 1 km horizontal grid spacing of a historic extreme event that occurred over Liguria: the 1915 San Fruttuoso case. The proposed approach focuses on the ensemble Weather Research and Forecasting model runs that show strong convergence over the Ligurian Sea, as these runs are the ones most likely to best simulate the event.

We present the results of several independent proxies of summer SST and upwelling SST from the Oman margin indicative of monsoon strength during the early Holocene. In combination with indices of carbonate preservation and bottom water redox conditions, we demonstrate that a persistent solar influence was modulating summer monsoon intensity. Furthermore, bottom water conditions are linked to atmospheric forcing, rather than changes of intermediate water masses.

In this manuscript, we present the results of our study conducted for a sediment core (ARC4-BN05) collected in the Arctic Ocean. Detailed examination of clay and bulk mineralogy along with grain size, content of Ca and Mn, and planktonic foraminiferal numbers in core ARC4–BN05 provides important new information about sedimentary environments and provenance. Based on these proxies, we try to reveal late to middle Pleistocene glacial history.

Climate-driven trends in fluorescent organic matter (OM) markers from Antarctic ice cores revealed fluctuations over 21.0 kyr, reflecting environmental shifts as a result of global ecosystem response in a warming climate. Precursors of lignin-like fluorescent chemical species were detected as OM markers from the Last Glacial Maximum to the mid-Holocene. Holocene ice contained the most complex lignin-like fluorescent OM markers. Thus, ice cores contain paleoecological OM markers of Earth’s past.

The purpose of this study is to contribute to the present knowledge of paleo data assimilation techniques by addressing the following two questions: (i) Does the off-line regime naturally appear for the assimilation of tree-ring-width records into an AGCM? (ii) Is the fuzzy logic (FL)-based extension of a forward model still useful to improve the performance of a time-averaged ensemble Kalman filter technique when a climate model is used?