An improved understanding of Madden-Julian Oscillation (MJO) dynamics and predictability is of utmost importance for extending weather forecasts and developing seamless climate predictions that are increasingly in demand for mitigation and adaptation to climate change. The lack of understanding and inadequate treatment of multi-scale convective organization and air-sea interaction are among the major stumbling blocks for the numerical prediction of intraseasonal variations.
Our preliminary examination of the development of the wet phase of the MJO event (heretofore referred to as “MJO initiation”), which occurred in late November 2011 over the Indian Ocean (IO), suggests that DYNAMO observations have provided an unprecedented dataset from a “natural laboratory” experiment.
This proposal articulates an endeavor to investigate aspects of MJO initiation, including the onset and development stages of an MJO wet phase, over the IO. The objective is to understand the roles of the multi-scale convective organization and interaction as well as air-sea interaction during MJO initiation. The overarching questions that serve as foci for the proposed research are:
1) How is deep convection organized during MJO initiation in the DYNAMO period (for each individual active MJO event)? What are controlling factors for the wet phase onset? How and to what extent do convective and eddy upscale transports of heat, momentum, and moisture impact MJO initiation?
2) How and to what extent does oceanic mixed layer/SST feedback influence MJO wet phase onset? What is the role of the precipitation-salinity-SST feedback in MJO development?
We hypothesize that MJO initiation is not a static thermodynamic process and must be conditioned by dynamical processes and involve feedbacks from meso-synoptic scale convectively coupled systems. The multi-scale and air-sea interaction play a significant role in MJO initiation. Our specific efforts focus on two major thrust areas dealing with the oceanic MJO initiation specifically arising from (a) multi-scale convective organization and interaction during MJO initiation and (b) upper ocean response and feedback in MJO initiation. To meet the challenge of understanding these nonlinear processes, we shall adopt a strategy of synergetic analysis by combining diagnostic and hierarchical numerical modeling approaches.
This proposal is submitted to one of the priority areas of NOAA/CPO/ESS Program: “Understanding and improving prediction of tropical convection using results from the DYNAMO Field Campaign.” This project will extensively use data collected during DYNAMO and focus on two physical processes deemed to be critical to MJO initiation: “the dynamic evolution of the cloud population and air-sea interaction.”
Completion of this project will make a significant contribution to NOAA’s goal in delivering cutting-edge extended range and seamless predictions to the nation and global community, which would serve as a foundation for climate adaptation and mitigation. Specifically, this project is expected to contribute to NOAA’s Next Generation Strategic Plan (NGSP)’s five-year climate objectives to improve scientific understanding of changing climate and its impact.