Aircraft Observations of Dry Air, ITCZ, Convective Cloud Systems and Cold Pools in MJO During DYNAMO

International audienceOne of the most challenging problems in predicting the Madden-Julian Oscillation (MJO) is the initiation of large-scale convective activity associated with the MJO over the tropical Indian Ocean. The lack of observations is a major obstacle. The Dynamics of MJO (DYNAMO) field campaign collected unprecedented observations from airborne, land and ship based platforms from October 2011-February 2012. Here we provide an overview of the aircraft observations in DYNAMO, which captured an MJO initiation event from November-December 2011. The NOAA WP-3D aircraft was stationed at Diego Garcia and the French Falcon-20 aircraft on Gan Island in the Maldives. Observations from the two aircraft provide a unique data set of three-dimensional structure of convective cloud systems and their environment from the flight level, airborne Doppler radar, microphysics probes, ocean surface imaging, GPS dropsonde and Airborne eXpendable BathyThermographs (AXBT) data. The aircraft observations revealed interactions among dry air, ITCZ, convective cloud systems, and air-sea interaction induced by convective cold pools, which may play important roles in the multiscale processes of MJO initiation. This overview focuses on some key aspects of the aircraft observations that contribute directly to better understanding of the interactions among convective cloud systems, environmental moisture, and the upper ocean during the MJO initiation over the tropical Indian Ocean. Special emphasis is on distinct characteristics of convective cloud systems, environmental moisture and winds, air-sea fluxes, and convective cold pools during the convectively suppressed, transition/onset, and active phases of the MJO