Ice2ice researchers Hannah Kleppin and Markus Jochum has published together with coworkers from Colorado a paper titled “Stochastic Atmospheric Forcing as a Cause of Greenland Climate Transitions” in Journal of Climate. The abstract is presented below and the full article can be found here.

Abstract

An unforced simulation of the Community Climate System Model 4 (CCSM4) is found to have Greenland warming and cooling events that resemble Dansgaard-Oeschger-cycles in pattern and magnitude (Figure 1a). With the caveat that only 3 transitions were available to be analyzed, we find that the transitions are triggered by stochastic atmospheric forcing. The atmospheric anomalies change the strength of the North Atlantic subpolar gyre, leading to a change in Labrador Sea sea-ice concentration (Figure 1b) and meridional heat transport. The changed climate state is maintained over centuries through the feedback between sea-ice and sea-level pressure in the North Atlantic. We discuss indications that the initial atmospheric pressure anomalies are preceded by precipitation anomalies in the West Pacific warm pool. The full evolution of the anomalous climate state depends crucially on the climatic background state.