Preliminary Regional Modeling Studies of the Initiation of Madden and Julian Oscillation

. A regional scale model of the atmosphere is used to study the initiation of Madden and Julian Oscillation (MJO) events in the Indian and western Pacific Ocean region. This model is based on the Pennsylvania State/National Center for for Atmospheric Research Mesoscale Model Version 5 (MM5). Initial and boundary condition data are derived from the National Center for Environmental Prediction (NCEP) reanalyses. Multi-year control and perturbation simulations are performed. Preliminary results show that this model is effective at simulating the important qualitative features of the climate of this region and of the slow propagation of convective systems associated with the MJO. Recent observational studies have suggested that the local generation of convective instability, rather than circum-global Kelvin waves, may be critical for defining both the initiation and period of MJO events. We test this hypothesis perturbation using several perturbation experiments. Preliminary results are presented