Stochastic dynamic simulation of the 100-kyr cycles in climate system

Abstract

Based upon the stochastic resonance theory, the formation mechanism of 100-kyr cycles in climate system is numerically studied in the perspective of stochastic dynamics. In this study, firstly we combine the idealized albedo model with the geological evidence and observation in climate system to construct a new albedo model. Secondly, a bistable nonlinear system is constructed by introducing the albedo model into zero-dimensional energy balance model. Finally, based on this new system, with the solar radiation cycles and stochastic perturbation simultaneously taken into account, the variation of 100-kyr cycles is analyzed by numerical simulations. The results show that, when the noise intensity reaches a certain value, the stochastic resonance can be triggered. However, the noise intensity in this level does not exist in the actual climate system. In order to explain the formation mechanism of 100-kyr glacial-interglacial cycles forced by the weak solar radiation cycles, besides the solar radiation stochastic perturbation, the stochastic dynamic effects of the other “non-solar” radiation stochastic perturbation in the climate change processes should also be considered. The stochastic dynamic simulations taking the two types of stochastic perturbation into consideration show that, when the two types of appropriately observable stochastic perturbation are introduced, the stochastic resonance also can be generated. In this situation, the contribution rate of solar radiation stochastic perturbation is about 38%, which proves the importance of solar radiation stochastic perturbation in the formation of 100-kyr climate cycles.