Diverse MJO Genesis and Predictability

Abstract The Madden–Julian oscillation (MJO) is the dominant intraseasonal wave phenomenon influencing extreme weather and climate worldwide. Realistic simulations accurate predictions of MJO genesis are cornerstones for successfully monitoring, forecasting, managing meteorological disasters 3–4 weeks in advance. Nevertheless, processes emerging precursor signals an eastward-propagating event remain largely uncertain. Here, we find that observed past four decades exhibit remarkable diversity with different seasonality can be classified objectively into types, namely, a novel downstream origin from westward-propagating (WPISO; 20.4%), localized breeding Indian Ocean suppressed convection (IOSC; 15.4%), upstream succession preceding weakly dispersive (WD; 25.9%), strongly (SD; 38.3%) MJO. These types associated oceanic background states, characterized by central Pacific cooling, southern Maritime Continent warming, eastern warming WPISO, IOSC, WD, SD respectively. type also favored during easterly phase stratospheric quasi-biennial oscillation. Diverse convective initiations possibly imply various kinds propagations subseasonal reforecasts indicate robustly distinct prediction skills diverse genesis. A window opportunity skillful week probably opens aid WPISO-type precursor, which has increased predictability primary onset 1 week. findings suggest diversified skillfully foreseen monitoring unique serve as benchmarks evaluating contemporary models’ modeling predicting capabilities.