The interaction of diurnal cycle of convection and the propagation of the Madden-Julian Oscillation across the maritime continent

The interaction of diurnal cycle of convection and the propagation of MJO across the Maritime Continent (MC) is examined using cloud permitting regional model simulations. A pair of control and no-diurnal cycle simulations of the November 2011 MJO episode observed during the AMIE/DYNAMO field campaign are performed. In the no-diurnal cycle experiment, the incoming shortwave radiation at the top of the atmosphere is maintained at its daily mean value. MJO signal propagating across the MC is weakened with much of the convection stalling over the islands of Sumatra and Borneo in the simulation with the diurnal cycle, in contrast to that in the no-diurnal cycle experiment. During the active phase of the MJO, the solar diurnal cycle enhances daily mean precipitation over the islands and reduces it over the adjacent seas. This impact of the solar cycle on mean precipitation is comparatively small during the suppressed phase of the MJO. Non-linear interactions between surface fluxes and convection that give rise to the observed behavior of diurnal cycle during MJO propagation across the MC will be discussed.