The Impact of the Stratiform Heating on Madden-Julian Oscillation

The impact of stratiform heating on the Madden-Julian Oscillation (referred to as MJO) is investigated. The nonlinear CISK (Conditional Instability of Second Kind)-Kelvin wave equations with both cumulus heating and stratiform heating are reduced to ordinary differential equations by using a spectral truncated method. With the help of the fourth-order Runge-Kutta method, the numerical solutions are obtained. It is found that the MJO could also be excited by the only stratiform heating. Meanwhile, the combined role of both cumulus and stratiform heating can enhance the MJO. However, the chaotic solutions under the cumulus heating can become regular solutions by considering the stratiform heating. In this case, the regular solution looks like a propagating envelope wave packet, whose periodicity is more evident with the period being easily within the range of 30－60 days.