Differences in timing between Figs. Haertel, : Zonal and vertical structure of the Madden—Julian oscillation. Journal of the Atmospheric Sciences September , Vol. The systematic deepening of convective clouds prior to the active phase has led many to argue that the free-tropospheric moistening by the antecedent populations of cumulus and congestus clouds is important for preconditioning the environment for subsequent deep convection Johnson et al. An overview of the two MJO events sampled in DYNAMO is provided in section 3 for large-scale context, wherein the periods of focus for the diurnal cycle analysis section 4 are defined. The diurnal cycle in the tropical atmosphere is clearly an open subject in need of greater investigation.