Air-ice-ocean feedback mechanisms, which are not conventionally incorporated within either climate or glacial models, are investigated to illustrate their potential role in generating ice advance/retreat on the time scale of 103–104 years; i.e. for examining the internal causes for the ice oscillation.
Three main feedback loops are found from a coupled air-ice-ocean model developed in this paper: (a) ice advance → lower air temperature → ice freezing → ice advance; and (b) ice advance → higher ocean temperature → ice melting → ice retreat; (c) ice advance/retreat → modification of evaporation rate → change of ice accumulation rate and sea-level height → ice advance/retreat. The relative strength of the three feedback mechanisms determines the characteristics of the modes: growing or decaying, oscillatory or non-oscillatory. The solutions show the generation of growing oscillatory modes with the time scale of 103–104 years in certain parameter ranges.