Talk by Jesper Sjolte – Københavns Universitet

Talk by Jesper Sjolte

Title: Climate field reconstructions: combining an isotope enabled GCM with seasonal ice core data.

In this talk I will present seasonal climate field reconstructions of temperature and sea level pressure for the North Atlantic region. The reconstructions are based on seasonal and annual ice core records of δ18O from Greenland and a 1200-year simulation with a coupled atmosphere-ocean model including isotope diagnostics. The method matches the spatio-temporal variability of the model δ18O to the variability of the ice core δ18O. Using an ensemble approach the best matching years from the model are used to reconstruct the corresponding variability of pressure and temperature. While the best results are achieved for the winter season, there is also potential for using the method for summer and annual data. As recently shown (Sjolte et al., 2018) the reconstruction for winter has good skill, not only for the North Atlantic Oscillation (NAO), but also for secondary circulation patterns (Eastern Atlantic pattern, Scandinavian blocking). I will also discuss the reconstructed response to volcanic and solar forcing, and offer some perspectives on climate forcing during the Little Ice Age.

Sjolte, J., Sturm, C., Adolphi, F., Vinther, B. M., Werner, M., Lohmann, G., and Muscheler, R.: Solar and volcanic forcing of North Atlantic climate inferred from a process-based reconstruction, Clim. Past, 14, 1179-1194, https://doi.org/10.5194/cp-14-1179-2018, 2018.