This project seeks to understand the role of convective momentum transport (CMT) in the lifecycle of the Madden-Julian Oscillation (MJO). The MJO is an envelope of organized convection that propagates from the Indian Ocean to the Pacific Ocean and constitutes the dominant form of intraseasonal precipitation and atmospheric circulation variability in the tropics. The MJO influences a variety of tropical weather and climate phenomena,including tropical cyclones (affecting hurricanes in the Gulf of Mexico), the onset and intraseasonal fluctuations of the monsoons and rainfall over Asia, Australia, Africa, and the Americas, and the onset of El Nino events. CMT refers to the vertical transport of horizontal momentum that takes place due to the updrafts and downdrafts in convective clouds. Traditional theories of the MJO have emphasized the role of convective clouds in transporting heat and moisture, and in driving large-scale circulations through latent heat release. But some recent studies suggest that CMT may play a critical role for the development of the MJO circulation through a two-way dynamical interaction between the MJO and convectively coupled equatorial waves (CCEWs) within the much larger MJO envelope. Through detailed analysis of newly available datasets, including those produced during the Dynamics of the MJO (DYNAMO) field campaign, the principal investigators seek to achieve a comprehensive characterization of CMT associated with the MJO, and thereby improve our understanding of the role of cumulus effects on MJO development.
The MJO is of practical as well as scientific interest, given the many climate and weather impacts of MJO activity. The work performed here has the potential to improve MJO forecasts, through the development of parameterizations through which the effects of CMT can be included in numerical models used to produce long-range predictions of the MJO. In addition, In addition, the project provides support and train a postdoc, thereby providing for the future scientific workforce in this area.
