Ice sheets respond to climatic changes over a wide range of periodicities (frequencies). On orbital timescales, geological evidence suggests that ice sheet volume and area appear to 'resonate' with insolation forcings at approximately 100kyr, 41kyr, and 23kyr frequencies. Temporal uncertainties in proxy-based reconstructions, however, mean that it is often necessary to assume that the way a ice mass resonates to environmental changes of a particular frequency is invariant. When we test these assumptions with model simulations, however, the results indicate that the style of ice sheet resonance is dependent both on the frequency of the insolation forcing, and on the background climate state experienced by the ice sheet.
People: Nick Golledge, Richard Levy, Rob McKay, Tim Naish, Dan Lowry, Stephen Meyers, Nick Sullivan