Woolnough et al. (2025) The Madden–Julian oscillation

Identification

• Journal: Elsevier eBooks
• Year: 2025
• Date: 2025-11-14
• Authors: Steven J. Woolnough, Charlotte A. DeMott, Daehyun Kim
• DOI: 10.1016/b978-0-443-31538-1.00012-9

Research Groups

• National Centre for Atmospheric Science, Department of Meteorology, University of Reading, Reading, United Kingdom
• Department of Atmospheric Science, Colorado State University, Fort Collins, CO, United States
• School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea

Short Summary

This chapter synthesizes the current understanding of the Madden–Julian oscillation (MJO), describing it as the primary mode of intraseasonal tropical variability, a planetary-scale eastward-moving disturbance with a 40–50 day period that modulates tropical convection and influences global weather systems.

Objective

• To describe the Madden–Julian oscillation (MJO), including its discovery, fundamental characteristics, and global impacts on tropical and extratropical weather systems.

Study Configuration

• Spatial Scale: Global, with a focus on tropical regions (Indian Ocean, West Pacific) and extratropical teleconnections. Planetary-scale (wavenumber 1–2).
• Temporal Scale: Intraseasonal (broad spectral peak around 40–50 days), subseasonal timescales. Historical context from the 1970s to present.

Methodology and Data

• Models used: Not applicable; this is a review chapter synthesizing existing literature.
• Data sources: Synthesis of findings from historical upper-air wind observations, satellite remotely sensed clouds, and previous research literature.

Main Results

• The Madden–Julian oscillation (MJO) is identified as the leading mode of intraseasonal variability in the tropical climate system.
• It is characterized as a planetary-scale, eastward-moving disturbance with a broad spectral peak around 40–50 days.
• The MJO modulates tropical deep convection and precipitation, providing a tropical source of Rossby waves that propagate into the extratropics, influencing midlatitude weather.
• Its discovery involved spectral analysis of upper-air wind observations, revealing coherent, out-of-phase oscillations between upper and lower tropospheric winds and an eastward propagation of large-scale circulation cells.
• Early satellite observations confirmed the convective anomalies associated with the MJO.
• During boreal summer, the MJO in the Indian Ocean and West Pacific exhibits both strong eastward and northward propagating components, closely linked to the active/break cycles of the Asian summer monsoon.

Contributions

• Provides a comprehensive synthesis of the Madden–Julian oscillation, detailing its discovery, fundamental characteristics, and global impacts, serving as a foundational reference for subseasonal-to-seasonal prediction.

Funding

• Not explicitly stated within the provided text for this specific chapter.

Citation

@article{Woolnough2025MaddenJulian,
  author = {Woolnough, Steven J. and DeMott, Charlotte A. and Kim, Daehyun},
  title = {The Madden–Julian oscillation},
  journal = {Elsevier eBooks},
  year = {2025},
  doi = {10.1016/b978-0-443-31538-1.00012-9},
  url = {https://doi.org/10.1016/b978-0-443-31538-1.00012-9}
}