Forced Lorenz attractor and the feasibility of drought and excess rainfall prediction

Abstract

Atmospheric system is known to be chaotic with different regimes in different time scales. In the seasonal time scale, there are drought and excessive rainfall periods. The feasibility of prediction of such regimes has been studied with Lorenz system which has a strange attractor with two wings which may crudely compared with the atmospheric regimes. As the atmospheric regimes are strongly dependent upon boundary forcings, a forcing in the original Lorenz system has been introduced. It is observed that with certain forcings the shape of the attractor shifts towards one of the wings of the original attractor. It shows that if proper forcings are known, at least that part of monsoon variability which depends mostly on the boundary forcing may be `predictable.