Aircraft observations of dry air, the itcz, convective cloud systems, and cold pools in MJO during dynamo

A major international field campaign supported by the Dynamics of the Madden?Julian Oscillation (DYNAMO), the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY), the Atmospheric Radiation Measurement Program (ARM) MJO Investigation Experiment (AMIE), and the Littoral Air-Sea Processes (LASP) programs took place over the Indian Ocean with an intensive observing period (IOP) from 1 October 2011 to 15 January 2012. The mobility of the aircraft proves to be vital in capturing some key features, such as the spatial distribution of the large-scale water vapor and the small-scale SST variations associated with convective cold pools, filling a gap from the ship- and land-based station observations. It was found that dry air intrusions from the subtropics may suppress convection in the ITCZ, which is favorable for the onset of the equatorial convection during MJO initiation. Distinct characteristics were found in the convective structure and microphysical properties of MCSs during the suppressed, transition/onset, and active phases of the MJO. The atmospheric boundary layer depth and upper-ocean temperature are higher during the suppressed phase than during the active phase, and the air?sea temperature difference and sensible fluxes are larger during the suppressed phase of the MJO.