Modeling the Madden-Julian oscillation and convectively coupled Kelvin waves

As presented in the papers of Harris et al. and Kiladis et al. (this conference), there are two distinct large-scale eastward propagating disturbances in the moist convection fields of the tropical troposphere. They are commonly known as the Madden-Julian Oscillation (MJO), and the convectively-coupled Kelvin wave. In this paper, we explore aspects of their dynamics with the use of 2 models. The first model solves the dry primitive equations to simulate the 3-dimensional dynamical structure forced by large-scale atmospheric heatings that propagate to the east at their respective phase speeds of around 5 m/s and 15-20 m/s. This dry model well simulates the stratospheric waves radiated by the moving heat sources, as well as some aspects of the observed tropospheric structure. The second is a simple moist model of the troposphere with 3 levels, exploring the different dynamical mechanisms behind the different propagation speeds of the MJO and moist Kelvin wave.