The theoretical basis and application of an analogue-dynamical model(ADM) in the Lorenz system is studied.The ADM can effectively combine statistical and dynamical methods in which the small disturbance of the current initial value superimposed on the historical analogue reference state can be regarded as a prediction objective.Primary analyses show that under the condition of appending disturbances in model parameters,the model errors of ADM are much smaller than those of the pure dynamical model(PDM).The characteristics of predictability on the ADM in the Lorenz system are analyzed in phase space by conducting case studies and global experiments.The results show that the ADM can quite effectively reduce prediction errors and prolong the valid time of the prediction in most situations in contrast to the PDM,but when model errors are considerably small,the latter will be superior to the former.To overcome such a problem,the multi-reference-state updating can be applied to introduce the information of multi-analogue and update analogue and can exhibit exciting performance in the ADM.
On the basis of the quasi-geostrophic vorticity equation,theoretical research has been down upon the evolution of the amplitude of solitary Rossby waves employing the perturbation method,and come to the conclusion that the evolution of the amplitude satisfies the variable coefficient Korteweg-de Vries(KdV) equation.
