Fifty Years of Research on the Madden‐Julian Oscillation: Recent Progress, Challenges, and Perspectives

Abstract

Since its discovery in the early 1970s, the crucial role of the Madden‐Julian Oscillation (MJO) in the global hydrological cycle and its tremendous influence on high‐impact climate and weather extremes have been well recognized. The MJO also serves as a primary source of predictability for global Earth system variability on subseasonal time scales. The MJO remains poorly represented in our state‐of‐the‐art climate and weather forecasting models, however. Moreover, despite the advances made in recent decades, theories for the MJO still disagree at a fundamental level. The problems of understanding and modeling the MJO have attracted significant interest from the research community. As a part of the AGU's Centennial collection, this article provides a review of recent progress, particularly over the last decade, in observational, modeling, and theoretical study of the MJO. A brief outlook for near‐future MJO research directions is also provided.

Equatorial modons in dry and moist-convective shallow-water systems on a rotating sphere

“…2020; Jiang et al. 2020) give a comprehensive picture of the present state of the theory of the MJO and we briefly summarize some below. Already upon its first identification, Madden & Julian (1971) hypothesized that deep convection is crucial for the MJO dynamics.…”

Large-scale controls of propagation of the Madden-Julian Oscillation

“…Modeling the MJO, however, remains a grand challenge for the climate research community [4][5][6] . Until most recently, the observed eastward propagation of MJO convection and associated circulations could only be simulated by a limited number of global climate models (GCMs).…”

“…Meanwhile, a lack of consensus exists on the fundamental physics of the MJO 6,10 . One traditional body of thought considers the MJO to be a couplet of the equatorial Kelvin and Rossby waves.…”

Tropical modulation of East Asia air pollution

“…For instance, it is anticipated that when MJO phase 5-6 is detected in the tropics, the PM10 in East Asia increases with a high chance of heavy pollution days one to two weeks later. Since numerical models are capable of predicting the MJO for two to three weeks in advance 26,27 , the MJO-PM10 connection reported in this study can open a new window of opportunity for subseasonal PM10 prediction in East Asia.…”