Coupled climate model simulation of Holocene cooling events: solar forcing triggers oceanic feedback

H. Renssen (1) , H. Goosse (2) , R. Muscheler (3)

1 FALW - Faculty of Earth and Life Sciences [Amsterdam]
2 UCL-ASTR - Institut d'Astronomie et de Géophysique Georges Lemaître
3 GSFC Climate and Radiation Laboratory

The coupled global atmosphere-ocean-vegetation model ECBilt-CLIO-VECODE is used to perform transient simulations of the last 9000 years, forced by variations in orbital parameters, atmospheric greenhouse gas concentrations and total solar irradiance (TSI). The objective is to study the impact of decadal-centennial scale TSI variations on Holocene climate variability. The simulations show that negative TSI anomalies can trigger temporary reorganizations in the ocean circulation that produce centennial-scale cooling events that are consistent with proxy evidence for Holocene cold phases. In the model, reduced solar irradiance leads to a relocation of the site with deepwater formation in the Nordic Seas, causing an expansion of sea ice that produces additional cooling. The consequence is a characteristic climatic anomaly pattern, with cooling over most of the North Atlantic region and drying in the tropics. Our results suggest that the oceans play an important role in amplifying centennial-scale climate variability.

Domaines: Interfaces continentales, environnement; Sciences de la Terre

H. Renssen, H. Goosse, R. Muscheler. Coupled climate model simulation of Holocene cooling events: solar forcing triggers oceanic feedback. Climate of the Past Discussions, 2006, 2 (3), pp.209-232. ⟨hal-00298128⟩