MJO Propagation Characteristics over the Maritime Continent

This study examines MJO propagation characteristics and mechanisms over the Maritime Continent. The Maritime Continent plays a critical role in sub-seasonal to seasonal predictive skill of the atmosphere because intraseasonal tropical convection and the midlatitude jet stream interact strongly in this region, influencing subsequent weather downstream. While several phenomena have been proposed to influence MJO propagation over the Maritime Continent, their relative significance, interplay and precise mechanisms have not been examined in detail using observations, which is an essential step for model verification purposes. This study finds that the propagation characteristics of observed MJO events varies widely as it moves across the Maritime Continent (e.g., its propagation speed, intensity of convection, termination location). The MJO propagation characteristics are partially associated with the initial strength and width of convection over the Indian basin, low-frequency background state, and atmospheric and oceanic pre-conditions over the Maritime Continent. The interplay among these precursor signals associated with the variability of MJO propagation will be discussed.