New Insights on the MJO from DYNAMO
November 18, 2013
Richard Johnson
Hosted by Russ Schumacher
Abstract
The Madden-Julian Oscillation (MJO) has profound impacts on weather and climate worldwide, yet the basic dynamics of this oscillation are still not well understood. In addition, many forecast models have a difficult time predicting the MJO. An international field campaign – Dynamics of the MJO (DYNAMO) – was carried out in the Indian Ocean in 2011-12 to investigate MJO initiation with the goal of improving both basic understanding and prediction. The primary concentration of field observing systems was in October and November 2011. Fortunately, two prominent MJO events occurred during this two-month period.A number of findings from DYNAMO support previously held ideas regarding the characteristics of the MJO. For example, the transition from shallow cumulus to congestus to deep convection to stratiform precipitation throughout the life cycle, now a paradigm for the oscillation, was also observed during DYNAMO. However, several new and intriguing results are also emerging: a complex interplay between the ITCZ and the MJO, a stepwise evolution of the moistening process during the initiation phase, pronounced modulation of the tropopause by the MJO, an important role of the diurnal SST cycle in the developing phase, and downstream effects of Sumatra island on the characteristics of the MJO and tropical cyclogenesis over the Indian Ocean. These new observations are expected to lead to eventual improvements in prediction of this complex, global-atmosphere phenomenon.