A stochastic excitation model for the study of the chandler wobble

Based on the hypothesis that the Chandler wobble is excited by stochastic motions, a nonlinear, stochastic model is proposed consisting of a random Heaviside step function and an Eulerian centred differential scheme for a linear oscillator with drag. The model is studied both analytically and numerically. From a statistical analysis of the time series of effective atmospheric angular momentum it is shown that the stochastic component can excite 28–40% of the amplitude of the Chandler wobble. Finally the hypothesis of stochastic excitation is discussed.